Using pubkeys to log in is so great. It's self-custody for user identity. I can't wait for it to take off, but right now it's hampered by two things:

- requiring a browser extension, and

- the backup/recovery story

There is FIDO with passkeys, which is built in to OSes, but you can't manually back up your keys, and there is no mechanism for backup besides letting Google do it for you. Then you're still tied to a Google account.

With Nostr extensions you can see and manually back up your keys, but the extension is required. This makes it especially hard on mobile because the major mobile browsers don't support extensions. So you have to use an alternate browser.