Con: ridiculous waste of emulsion adding up to $$$$$$$.

When coating an 11"x14" screen with emulsion in silkscreening I use ~4 oz. When coating paper for an 11"x14" pt/pd print I use ~1.5mL.

Maybe I'm misunderstanding what you're asking. The only thing I can think that would be similar is the photo-resist emulsion on the screen. If you're talking about applying the pt/pd emulsion through a screen that has already been prepared for printing then you'd waste even more emulsion.

Silkscreening is done the way it is because the constituents for the process are so cheap.