I'd like that for my iPhone. I have this fear that I'm going to leave it in my pocket when I jump into the pool or wade out into the ocean. Also, the idea of leaving it on the pool deck without worrying about splashes would be nice (of course, someone would probably step on it).
I wonder how much this affects the sound quality of the built-in microphone and speakers. Obviously, they'd get coated, too, and it seems it would pretty much ruin them to coat them with something permanent.