Most schools that I've seen have prompts/allow for optional essays. You should write an optional essay if you have something to say. If you don't have anything meaningful to write about, then that essay is, at best, not going to help you.
Yeah, definitely sounds like a yield protection thing. I'm not really familiar, but if it is optional I just can't see how it is going to help. I guess it depends on your stats and the school you're applying to.
I got a 164 and I have a 3.71 GPA. I'm in a grad program at Georgetown right now and was hoping to do a dual degree (could do it if I'm admitted this cycle) but it doesn't seem likely :/ Quite bummed.