Comment by palata

Not sure what you are trying to say.

I can easily imagine having a way to prove my age in a privacy-preserving way: a trusted party knows that I am 18+ and gives me a token that proves that I am 18+ without divulging anything else. I take that token and pass it to the website that requires me to be 18+. The website knows nothing about me other than I have a token that says I am 18+.

Of course, I can get a token and then give it to a child. Just like I can buy cigarettes and give them to a child. But the age verification helps in that I don't want children to access cigarettes, so I won't do it.

The "you are a human" verification fundamentally doesn't work, because the humans who make the bots are not aligned with the objective of the verification. If it's privacy-preserving, it means that a human can get a token, feed it to their bot and call it a day. And nobody will know who gave the token to the bot, precisely because it is privacy-preserving.