Even better: Imagine a world where you could just host your public keys on e.g. mydomain.com/.well-known/jwks.json, you register with a service provider with me@mydomain.com, then the service automatically pulls public keys from that. Then, all you have to do is sign new keys with an appropriate audience like aud:"serviceprovider.com".

And for the public email providers, a service like Gravatar could exist to host them for you.

Wouldn't that be nice.