Gaming

Depends on the TV. For gaming, it would be essential that it has some form of gaming/low latency mode.

Also, why would you pay extra for a "good" main board? That's literally the one thing where you can go cheap without a problem if you're not investing in the high-end segments of the other components.

As a sidenote: have you looked at something like a SteamDeck for your kid? It's a full fledged PC that you kid can hook up to the TV and if you want to watch something on it the kiddo can still use it with the build in display. the base model is also dirt cheap for what you get.

A TV will do, for a child. He doesn’t NEED anything fancy. Will it be a great experience? Absolutely not. Others here have already gone over the issues. That being said, if cash flow is an issue (relatable), it’ll be fine. Console gamers have been doing it for literal decades. I also used to do it, back when I was a kid, when we had an old 480i TV. Your kid should be grateful that he can play his games. People can spend too much time worrying about not getting the best experience (especially when giving advice to others), when it’s often not needed.

Is this a smart idea?

For Roblox and Minecraft, a TV should be perfectly fine and in fact excellent. I will go out on a limb here and say that even for most 'real' games a TV is fine. The latency associated with TVs is most noticeable in FPS games. For other genres like strategy, third-person adventure games etc, I do not think it matters as much if at all. Many people, especially those who have not used a low response / gaming monitor, do not even notice a lag at all (Note: You will find many such people in real life but never ever on the internet). It would be nice of course if your TV had a "Game Mode" which lowers latency, but it may not necessarily be there in a 10-year-old TV (though it was not that uncommon even back then, so do look for it in your TV settings).

Regarding programming on the TV, I think the situation is slightly different. Using small text in general doesn't work for me at all on a TV. Most TVs, other than OLEDs or recent non-OLED ones, don't seem to handle text well enough in my experience. There's either ghosting or some other manner of artifacts which makes the text harder to read compared to a monitor (apart from the distance from TV involved). I commonly see this issue even with office televisions used for mirroring laptop output. Maybe playing around with sharpening and other settings might get it to work well enough though and it really depends on the specific TV in question.

Overall, I feel you should be fine, at least for gaming, but probably for programming as well. I have a couple of gaming rigs hooked up to my living room and bedroom TV's and I quite enjoy gaming on them. The much larger screens and ability to lounge about while gaming more than make up for any perceived or actual lag for me.

I hope your kid and you have a great time with your new setup. Have fun! :)

I appreciate that you're doing this on a budget. The only thing I can say is that a monitor doesn't represent a significant portion of the build budget. A basic monitor can be had for under $100. Honestly a lot of tech-oriented people have extras laying around. I've had 3 extra 1080p monitors in my garage for the last few years. It's entirely possible that someone may be giving one away near you.

I've done it with an old cheap tv and it sucked and i got ghosting and choppy refresh rate. I'm sure if you get a decent modern tv would be fine though. I'd also want to check latency.

Disclaimer: i don't know much about anything

I am most concerned about the logistics of mouse and key slouched over a table sitting on the couch. Maybe some sort of desk setup in front of the TV? 1080p monitors are very cheap second hand. Sometimes thrift stores have them even.

What's the resolution on the TV? I'd think you'd want at least 1080p for it to be effective.

You can absolutely use a TV, even for FPS games. If the response time is terrible it might impact FPS games, but every other genre should be fine even if the input lag is significant.

I used a TV myself for 2-3 years at one point. I was playing Destiny 2, an FPS game, when it finally died on me lol.

Have been gaming in front of a 44-inch 4k TV for years (sorry eyes) with no issues. The biggest thing is making sure the TV has some sort of low latency or "gaming" mode that will turn off the TVs post-processing. WITHOUT THAT, the other commenters are right that the input lag may be unplayable.

I don't see anyone mentioning it, but TVs differ from Monitors in one major way: the pixel representation on the TV is downsampled. This affects the rendering of text on the screen, but it is usually just the red channels that do this, so the human eye doesn't pick up on it terribly well in most cases.

Personally, I can tell with Windows font rendering on a TV. Windows already uses that weird blue-red shift thingy to anti-alias the fonts and I don't like that either.

All that said... does it matter? No, not at a distance and with the font size jacked up to 200%.

I second skipping over the motherboard for a budget-but-upgradable build. Video card is the most important thing, so as long as the motherboard supports it, it's good enough, and the vast majority will.

That said, second hand graphics card still isn't a bad idea, since when you're finished with the build some years down the line, the video card will be the oldest component.

Instead, get an NVMe M.2 hard drive, and a PCIe expansion for it since that budget motherboard probably won't have native support. Expansion cards costs hardly anything relatively, and native support can be added to the list. A great hard drive makes ok RAM better than OK and cuts level loading times significantly. Honestly, adding a great hard drive to even some tiny budget dell desktop with built in graphics makes an ok budget gaming computer.

If there's money left over get a good sound card or whatever peripherals you'd prefer, maybe Wi-Fi/Bluetooth (budget mobo probably skips them) and RAM if the budget mobo is still a recent one. Despite the TV likely being good enough, too. I wouldn't focus on the motherboard until you're picking out the high-end CPU, which is expensive but also just a lower priority than the other stuff, so a good monitor is on that peripherals list, too.

That dell comment is from experience, I made one into a surprisingly decent Minecraft/Roblox machine for a relative. Only thing that stopped it was the HDD it used. A solid-state drive is sufficient, m.2 is just future-proofing.

No harm in trying it first. Beyond basic connectivity, here are some things you’ll need to check for.

You’ll want to make sure you can turn off overscan in your TV settings or the edges of what the computer will display will be cut off in the image. This can make navigating things like the Windows desktop a little difficult.

Then you’ll want to make sure responsiveness is acceptable. Perform any action (click something, type something in Notepad, etc.) and make sure the TV displays it instantly. If not, you will need to enable Game Mode on your TV if it is available. Sometimes a Sports mode will get you there too. If such a mode isn’t on your TV and there are no other settings that reduce the response delay, you’ll need a dedicated monitor.

If you’re OK on both of these things, the only thing left would be stuff like resolution and color matching. For the best image, make sure the computer is set to use the TV’s native resolution. This may not necessarily be the highest resolution available, FYI. As an example, I have TVs that are 720 native but will accept and display 1080, albeit things don’t look great at that scale. Your mileage may vary. For color matching, don’t worry too much about accuracy if you’re not doing things that require a perfectly calibrated display. Set the picture mode on the TV to whatever vivid/movie/sports/etc color mode works for you, but keep in mind some of these can affect the delay depending on the TV (see above).

I used a TV for years. Didn't bother me at all and I gamed on it. Also tvs have built in speakers where as as far as I'm aware computer monitors don't. I suppose not all tvs are the same though so ymmv.