I can commend the designers for their ingenuity. It is neat. However, I don't think they consulted the intended market for folks that actually need and use a trailer. I don't always think the "If you build it they will come." adage is always correct.
I agree that at a show you might be able to snag a newbie into seeing how cute this is. And possibly get them to buy it. (I'm sorry I missed this unit at the Springfield Show. I was there, but have no interest in trailers, so even if I did see it, I'd just walk by. Oh well.)
In reality, not being able to open the tail gate on an SUV or minivan is a HUGE issue. Before we got our motorhome, I purchased a trailer-hitch mounted trunk for our minivan for our longer trips. I had to pay a fair amount extra for the type that pivoted away when mounted so you could access the tailgate and what was stored there. Without that access, we couldn't use that space. That would negate the purpose of using the hitch mounted trunk. If you can't access the stuff in the back of your vehicle because the trailer is folded up, then where would you put it? Oh yeah, in the trailer, so you don't need it to fold. But...now you can access the tailgate. So....just leave the trailer down.
The only time I could possibly see this as being helpful that hasn't been mentioned is in toll road calculations. You'd save an axle in toll costs. I doubt those savings would ever come near to the cost of this unit.
Blocking the vehicle's rear license plate is DEFINITELY a no-no. Our hitch mounted trunk has a lighted license plate frame and brake & turn signal lights as well.
Again, this is an interesting idea, but I think it's a solution to a problem that doesn't really exist for most, and when it IS a solution, it raises new problems if you try to use it.
As a business, I hope they do well. But if I were them, I've be working on the design of Version 2.0. :)
~Rick