EarthRoamers do come with a lot of off-grid extended-stay features. Things like the large solar banks, large water tanks, water filtration systems, and diesel appliances are all expensive items to add to a van.
But, I do agree with the practicality, or lack thereof. You don't really get much more space than a van, all in a footprint that takes up way space, a much higher cG, and non-existent visibility over the hood when driving off-road.
They look pretty bad ass though