A couple of weekends ago I was flipping through channels and came in at the end of a home repair show (not sure which one). On the show they were replacing the drywall in a room but instead of using mud to tape just the joints, they were putting a thin film of plaster over the whole wall. The reason they gave was that it eliminated the dust from sanding the mud and it gave a smoother suface for painting. I'd never heard of this before and was wondering if it really worked. Are there any advantages/disadvantages of one method versus the other?