Dumb question. What makes poopie suits worse than regular PT wear?
I can't speak specifically to poopie suits, since when I went through we didn't wear them, but I think the larger point is that OCS is designed to mentally destroy you for the first 3-6 weeks and then slowly put you back together, building your confidence up so that by graduation you feel ready to hit the fleet running. That mental destruction takes many forms - head shaving, no watches/concept of time, dressing in a way that makes you look stupid relative to the other classes (whether it's poopie suits, rolling vice blousing pants, PT gear for H class), or DI mind games.
So, I wouldn't get hung up on the specifics; I'd just go into it with 100% conviction you're going to get through it, regardless of what they throw at you.