Nope, won't work.

• something that is edible has to be soluble in water, thus, over time, the cup will leak.
• making a cup taste good and be structurally sound?
• we could eliminate waste build up if we burned our trash in two stage burning chambers and used that heat to create electricity.
• the restaurant industry is gone. It won't exist much longer, thus the reason for this line of inquiry will be dead.