“Looks like something you would put on he bed of your pickup truck for the weekend.”
It is a trailer. Look at the side and you can see the skirts over the tires.
They may have had to do that to meet local code: A lot of jurisdictions won't allow 'tiny houses' to be built on a permanent foundation, so people get around that by building on a trailer.
I don't know if that is the case in this particular instance, but I do know that it is like that in quite a few municipalities and counties, across the nation.
Or maybe they don't own the land that it is on, and want to be able to move it.