"Perhaps you can clarify the distinction?"

I'll call it self improvement when a substantial, nontrivial body of code is automatically developed, that is applicable to domains other than gameplaying, as opposed to playing a slightly different version of the same game. (Note that it was substantially the same strategy that won the second time as the first time, despite the rules changes.)

"A paperclip maximizer has no need for an intuitive user interface."

True if you're talking about something like Galactus that begins the story already possessing the ability to eat planets. However, UFAI believers often talk about paperclip maximizers being able to get past firewalls etc. by verbal persuasion of human operators. That certainly isn't going to happen without a comprehensive theory of human psychology.