NLA: Nostr Login Apps?
Liwn apps: Login-with-Nostr apps?
L-07 apps: Login with NIP07?
These will have a continuous use case with potentially 100% private login management, and the website doesn't need any info to manage access.
I've been thinking about how one would integrate this into WordPress. I think it's possible with a pseudo email address (npub....@nip07.nostr) in users table.
I'm pretty versed with WordPress and could totally build this plugin. Who'd use it other than me?