[ben_w]

The ability to make an infinite number of them.

And that most people have no idea how to verify any ID, so they need a system that turns any given form of ID into a nice and simple "yes" or "no".

I'm not at all clear what kind of ID is going to be genuinely useful for video calls, given we should only be trusting existing contacts anyway? But those things are why "private key" isn't sufficient in isolation.

[malermeister]

What's wrong with making an infinite number? You just need to check it against one public key.

[ben_w]

https://en.wikipedia.org/wiki/Sybil_attack

[mewpmewp2]

Why couldn't a mobile app that everyone uses work for this. The person who wants to verify who they are uses the app, does digital signing and the other person gets notificatiom and the certification.

[ben_w]

Sure, but that's basically the exact same value-add of Worldcoin, along with a bajillion other similar apps.