In this context (IIRC) smart means "if this zip contains a single folder with contents, directly extract that folder, but if the zip contains files and/or folders, extract all that to a new folder named the same as the zip file".
Some people zip folders while some people zip the files in a folder. Smart extraction just handles both automatically.
I mean, many (several?) sites tried optional subscriptions where you pay to get rid of ads, but that doesn't seem to have worked. Judging by the fact that most sites that have subscriptions instead of ads use pay walls.
People have come to expect free access, so if you can easily use an ad blocker, why would you choose to pay to remove the ads that a blocker removes for free.