I haven't tried using the camera underwater on it's own, but I used to have a couple Nikon Coolpix's and they never lasted very long.
On this last trip, I didn't use the strobe at all, but used the M52 120 degree wide angle lens.

The camera should take sharp pictures underwater without the housing, but the built-in flash is probably not ideal from a backscatter perspective, and the 24mm equivalent lens underwater makes it tough to get close enough to reduce the amount of water you are shooting through.
I'm definitely working on all this myself, just getting started on UW.