We have the shower/ toilet combo also. Never intended to use the shower but with a wife and young daughter, thought the toilet would be good.
Well, they use the toilet ALL the time, much nicer than going out into cold, dark or rain. The shower has only been used for the 5 year old, amazing how dirty a kid can get when camping
It's nice to also have a place for wet shoes on damper days as well and a good sized space for stuff when packing the camper ( lanterns, sleeping bags, etc)