Not sure how far along in the game you are, but I'm guessing not that far. That's only based on your rank of 'New Member'. I bring it up, because it might have some bearing on your post. The benefit you mention is only a plus if the girl answers 'Yes' which would open up some possibilities for future scenes I guess, but running around visiting the girls' rooms just to ask for sex kind of limits the other actions in the game. In your scenario of using 'max affection' or some other attribute, one would just need the appropriate console code to max everything out and then never leave the hallways. That might be an over simplification, but you get the idea.
Anyway, I believe the developer realized that there were/are times when the MC need the ability to talk with the girl one on one and rather then have to wait or send the others off to change their attire, it was easier to have them just visit the girl's room. The MC receives some valuable clues and advice from some of the girls, plus it also allows the MC to schedule future meetings with the girl(s) in various locations.
Glad you're enjoying the game.