what’s the point of a permanent bed?
You can have a garage under it. For bikes, BBQs and other pesky stuff like leisure batteries, spare wheels and heaters.
You can get up before your other half and not have to perch on the end of the bed for the two hours it takes them to wake up.
Means you can have proper comfy seats for traveling in.
Dumping area during the day. Don’t have to store all the bedding somewhere. Don’t have to set up the bed 28 times during your fortnight holiday.
On the other hand, drop down bed in a panel van…reduced headroom during the day, loss of dining/possibly cooking area when the bed is down, a big heavy waiting to drop on you during an accident, plus immensely complicated to build!