We've been tent campers for so long, we're still getting used to have our very own PRIVATE bathroom that goes everywhere with us:)
We used the CG showers this year mainly because we were still figuring out the WH...yeah, that sounds silly, but DH is being really careful about learning about this camper...yes, it's a pain sometimes, but it's really a good idea. Anyway, in one place we did not have water hook-ups (our second trip out) and we were too near the facilities, which were really nice, not to use them. We ALWAYS wear our flip-flops in public showers anyway.
We have used our shower (in the MH) and it's really sweet and we'll no doubt use it a lot more. But as was noted, we do pay for those CG showers, so why not use them? Sure we paid for our own private shower and toilet, but why not use theirs if it is convenient?