It seems like every semi-elaborately decorated cake is slathered in the stuff these days, and honestly, I'd be happy to never see it again. If I get a piece of cake with fondant frosting, I peel it right off (because it will come off in one whole piece) and go straight for the cake. I know technically it's edible, but the texture is so gummy and super-sweet that it completely overwhelms the cake it's supposed to be enhancing. I bet you could waterproof your deck with it.
I do agree that a professionally decorated cake, done with different colors of fondant and other frills, is often very beautiful. But it's usually better as a museum piece than as an actual dessert. Give me a good buttercream or chocolate frosting and I'm good. Anyone else?