I have frequently used the Fuji waterproof disposables for pool and beach pictures and really can't tell the difference between them and the regular camera, however....
...Sunscreen and disposable cameras DON"T mix!!! If you are wearing sunscreen and you pick up a waterproof disposable camera, it is next to impossible to get the sunscreen off of the plastic casing--if you don't get it off and it is near the lens it will cloud your pictures! I have found that the kids are the biggest culprit with this.