Let's say you've had your fill of the nomadic life and you want to get a piece of land and start homesteading. Cool. And of course you'd continue to live in the van while you build your earthship.
It's possible, though, to turn the van into the first room of your new abode. A partially buried van is more thermally efficient. Of course, you'd need to seal it properly and provide drainage and all that. So maybe it's not such a great idea after all. Oh well.