The problem is that traditional audio/video captchas are not proof of humanity either. Captchas are a method for increasing the amount of work that an automated client needs to do to access your site. They do not block bots, they just impose a cost.
They're designed to block bots, sure, I agree. But we are burying our heads in the sand if we think that captchas imply humanity. They don't. The tests that they impose are not rigorous or strong enough to do that. What audio/video captchas do in practice is impose a cost in front of automated access.
We'd like them to do more than that, but the tech hasn't really ultimately worked out in that direction so even though we'd like a captcha to prove that a user is a human, what the captcha enforces is just a cost-per-request. Sometimes that involves paying a human pennies to solve the captcha, sometimes it just means turning on accessibility features and piping the captcha into a text-to-speech service. Either way, the final request can still be trivially coming from a bot (and regularly is).
They're designed to block bots, sure, I agree. But we are burying our heads in the sand if we think that captchas imply humanity. They don't. The tests that they impose are not rigorous or strong enough to do that. What audio/video captchas do in practice is impose a cost in front of automated access.
We'd like them to do more than that, but the tech hasn't really ultimately worked out in that direction so even though we'd like a captcha to prove that a user is a human, what the captcha enforces is just a cost-per-request. Sometimes that involves paying a human pennies to solve the captcha, sometimes it just means turning on accessibility features and piping the captcha into a text-to-speech service. Either way, the final request can still be trivially coming from a bot (and regularly is).