I got to look at a couple.
The sales of the Via/Reyo have shown the floor plan is popular.
Sales of the Citation and Siesta Sprinter vehicles have shown the size fits a certain demographic - but those cannot meet the price point of many couples.
Some folks just don't want a diesel. It takes a long time and a lot of miles to make up the price difference between a diesel and a gas vehicle on better fuel mileage and reliability. Plus the Sprinter 'idle' misunderstanding has a lot of folks scared.
I'm seeing more and more vehicles of this size driven by much older couples (75+) as their last mobile RV choice. They pull in - setup quickly - spend a night - unhook to sightsee, etc - then come back daily.
It looks to be a tremendous pain to me, but I'm seeing folks doing it very happily.
The big reason for the Class A type body vs a Class C type cab in this size range is the front seats. The Class A body allows the seats to be part of the living area - with 90 degree or 180 degree rotation.