

How would you propose I prove to you at a reasonable certainty that I am an adult, without showing you my ID, or showing it to someone else you trust to tell the truth?
And also somehow prove that the ID I gave was not fake without the government that issued it telling you that it’s genuine?
Well, I actually could do it because I’m old enough that most of my accounts are already over 18 years old, but I don’t think requiring every new Pornhub user to wait 18 years is a reasonable solution.

It doesn’t. The website would ask for an id check, you would generate it on the processor side and give the randomized ID to the site so it could go check it’s valid and let you through. It can be used to verify an account permanently but without one, it would kinda act like a temporary 2FA code.