Removal of the URL structure of u/1 & u/2 etc.

I just recently saw that Flarum has 2 URL structures.

Why do we have the second one? Is it really necessary?

If not, I would like to see it removed from core.

arda Useful for having a permanent link to a user, regardless of username changes.

jordanjay29 OK, that's a great reason.

Anyone?