I know a whole lot of folks who live this way, mostly itinerant musicians.
While this is a much nicer build-- I think it's quite beautiful-- it is a lot closer to a custom conversion van most folks I know have much different, less successful experiences with DIY RVs.
To the folks who cite "stealth" as a rationale here, there are a lot of reasons why you might get kicked off a patch of ground... one persons "hack" is another person's criminal trespass. There are a lot of great places that you can camp out without getting hassled and without relying on other folks footing the bill for your plumbing and pavement.
To the folks citing mobility, I still don't see how that kind of van is more mobile than a pickup.
So while I think that it's really cool-- I gotta say that I think it would have to be cheaper / easier / more reliable to buy a pickup and 5th wheel or similar.