I still haven't heard a good reason.

I hear ideas from gamers and anti-big-tech folks, but none of it really sounds all that useful. But I'm also the kind of person who prints off their boarding pass at the airport because I prefer having a reliable piece of paper to get me on the plane.

Cryptocurrency and blockchains aside, I feel like if folks really cared about public authentication and proof of identity, then something like Keybase would be far more popular than it is. So idk, I've not been convinced yet.