We almost always use the bathhouse for showering, using the restroom is another story.
Our shower is barely large enough to turn around in without hitting the walls, let allow trying to lather up and such. Add to that a 6 gallon water heater, and you have a much more pleasant experience in the shower houses.
To avoid the athlete's foot issue (and any other fungus) we have a supply of shower shoes for everyone in the family, plus an assortment of various sized extras for guests or if the kids have friends with them.
A long hot shower feels really good after a day of exploring, hiking, bike riding, swimming, a campfire, and/or anything else that we might be enjoying during the day of camping.
Doug