Is it the additional data you give them to enter the giveaway?

Basically. You’re telling TP-Link that you’re a business that’s interested in selling their products. In return, their Sales team now has your information and can ~~pester you~~ tell you all about the latest TP-Link products.

Additionally, they’re putting their products directly in the hands of customers who could become even bigger customers. If you, as a company, decide you like the product, then you’re probably going to buy more of said product.

Finally, TP-Link is being selective about who gets the freebie—they’re not just handing them out willy-nilly. From the fine print:

Offer valid only for SolutionX partners. One Insight S445 (2.8mm) camera per qualified SolutionX partner. Approval is required, and TP-Link reserves the right to verify applications

So there’s probably some sort of “legitimacy threshold” you have to clear in order to get the goodies.

It could be the price of advertising, but I feel like this is one of those cameras where you need to connect it to your wifi or make an account with them

the catch is that you don't own that camera, only the manufacturer does. besides requiring an account and a connection to china to be able to use it, they have access to both your network, and to the camera feed. they'll use the network info to gather info about you, and the camera feed to train their face and gait recognition AIs, possibly also for intelligence