i looked at it more. it actually does make sense to put something requiring more hardware usage on a site if youre trying to prevent bots. itd slow them down a lot so theyre more likely to avoid those sites and go elsewhere
it really depends on how much they do it. if its not a ton its overall more effective to deter bots, as long as it isnt significantly reducing user experience. i tried loading one of the pages and it took about 2 seconds on my laptop