I started out as a power lifter to enhance football performance. No direct arm work. My arms blow When it comes to looks. Too small for my delts and chest and overall upper body thickness.
Direct arm work has brought them up. They still suck but their much better. Had I done direct arm work with powerlifting I think they'd probably be symmetrical.
Moral of the story: this is a stupid argument. Unless your blessed and you have 20" arms by benching and rowing do direct arm work.