It won't make that much of a difference against bosses, since most of them hit like a truck anyway (unless you play on baby easy mode). However it makes a WORLD of difference when backtracking for missed pickups.
uhm... I suppose the future updates will have more armor/clothes to go around, but as of now, I'm nude all the time, and when nude, the defense does nothing. I think.
Right, when Maya is wearing her armor the defense value mitigates some of the damage. But when naked, it doesn't matter how much defense rating she has. Indeed in future versions there will be a legit way to restore armor.