Something I never considered, I wonder how clicking to be a human works for people with disabilities. There’s gotta be accessibility features there, and I bet bots are abusing them.
At least for cloudflare "captchas", you don't have no solve anything, only click a button. Therefore it's pretty accessible. My guess is that they care less about whether you're a human or not, and more about imposing resource costs on any attacker, because solving those challenges requires a full browser runtime (ie. hundreds of megs of memory + some non-trivial amount of CPU time). That's significantly more expensive than you spamming requests.post() with on a thousand threads.