I've been known to describe it as a "tent on wheels". In Socal, desert camping is very common. If you have spent anytime in the desert you know the wind blows frequently, and when it blows it blows hard. So the people see the advantage of a "hard sided" tent. Most of my trips recently have been with my parents in their 40 ft RV. We have the shower and the toilet, and then my bed is more comfortable ( and more private) than staying inside with them.
Tom