What is the use case for choosing auth.getSession() over auth.getUser() and vice versa?

I understand that auth.getSession() retrieves the session, and getUser() retrieves the current user if exists. But since session returns the data containing the session and user, I am not clear as to what the use case is for both, since from my understanding they can pretty much do the same thing, except that getSession can actually refresh the tokens when needed.