In my understanding the user table is mostly there to store user authentication data. But then it also stores a users email and a users real name (email is a complicated thing and can't be tackled that easy).
The users real name is something a user can optionally set as preference (when allowed). And user properties seems to be the more natural place where that belongs.
It would also allow us to convert quite a lot of code to use UserIdentity instead of full user objects, since we no longer rely on User::getRealName().