Genuine question, what’s the point of them?.
The only thing I can come up with is that you can camp where there’s nowhere to pitch a tent.
Pretty much, so car camping anywhere that isn’t a campsite.
Also good if you want a campervan without having to have a second vehicle.
Or for 4×4’s where towing a campervan offroad isn’t really an option.
Or for trips where a caravan might be a good option, except your already towing a boat.
They also have a permanent mattress up there, so are supremely comfortable compared to any camping bed.
And most of the ‘soft’ ones fold out with an awning which gives propper 8ft+ headroom for getting changed!