This is the Daihatsu FC "Sho Case" concept, a light-weight, zero-emissions work vehicle of the future that just happens to house a large-screen TV. Why would you want to drive an environmentally sensitive mobile home theater? Lots of reasons; or none at all. Your choice.
Really, the point of the "Sho Case" concept is the new, liquid fuel cell that can fit under a vehicle's floor, giving designers a perfectly flat platform on which to work.
And what demonstrates "flat floor" quite like a kind of stage from which you can watch reruns of Barney Miller from outside the vehicle?
Okay, maybe not precisely what springs to mind. A mobile IHOP probably would have driven the whole "flat" point home more elegantly. But then, are there IHOPs in Japan? Yes. Yes, there are.
The Japanese love their maple syrup. Can you blame them?
Either way, the seats and steering wheel can be stowed, and the a fold-out exterior offers both additional workspace and ease of passenger ingress. In the future, mobile pancake houses will indeed stalk the streets of the world's cities. Mobile home theaters? Not so much.