Roof top tents only seem like a good idea if you travel in areas without wooded trails to me. I would always be concerned with damaging my expensive tent on low limbs or trees during off camber section. How much more comfortable can it be than a Coleman tent and air mattress?
Not bashing just discussing and wandering the true benefits of a tent that expensive from a guy with no experience with RTT's.
I completely agree, having and expensive tent up so high puts it at risk. On a pickup you and reduce the height of the tent, protecting it from trees and such but that's not a perfect fix. Not so easy on a 4rnr or an LC. Here are a few pros and cons as I see it.
Pros:
Easy setup and teardown, you can even leave the bedding in place for the most part.
Greater flexibility in camp locations, just need to park so the truck sits fairly level.
Always off the ground, rain or shine...
When open it provides a shaded area next to the truck.
Like a camper you can have more permanent power or other hookups since it is mounted to the truck.
Better mattress than a typical air mattress.
Cons:
Expensive!!!
For the price there are other options with just as many advantages.
Heavy compared to some other options.
Sits up high risking damage from trees and alike and raises the center of gravity.
You have to pack up camp to move the truck.
Have to climb a ladder or something to get in and out.
There's a lot more than I listed here but I'm not an expert either. It seems like the options are endless.