When you choose which one is better, you’re voting, but it’s kind of a temporary vote unless you keep going until it says “Thanks! It’s in your list now.” So you’re doing it right - it’s just listing the pieces you’ve already seen so you can compare the new one to each and then it figures out where to put in your list (called “your ticket” on a lot of pages).
There isn’t anything you can do with brain points just yet. Except show them off, I suppose! We keep toying with ideas about what to do with them. Every now and then, we have a contest in which your brain points play a role, so the more you have, the better.