I think it replaces email and text messaging, but it will take a very long time since many people don’t really want to own their keys.
Discussion
I think it will not take long because the protocol is extremely simple and easy to build upon. Just like how fast the web took off under the http protocol.
Oops didn't mean to repost my own post 😅
There are good key management protocols for dummies, such as multiple devices where one of your devices authorizes another, like Element on matrix. Even apple uses it like the watch authenticating the user to their laptop