/diy/ - Do It Yourself

Drywall retard here, having trouble understanding the different finishing levels. At the bare minimum the panel seams and screws would get taped and mudded, and sanded down. At this point, my understanding is you could just prime and paint the exposed drywall directly. Alternatively you can go to a higher level by skim coating the wall. If so what's the benefit of skim coating?

Next question: if you do skim coat, and want white walls, could you just leave it as-is and use the mud's natural color or do you have to paint?