chin-ups are probably better overall since they're a compound, unless you're trying to isolate, but bish prefers standing curls so he can check himself out in the mirrors - gritting his teeth on the pump and mouthing "oh yeeeah" and "you wanna fuck me?" over and over to himself. so its really about image and being seen, which is somewhat understandable if you weren't held enough as infant- perhaps like little bish.