Can be done on an MUP with care, it does go wide when starting and accelerating, but it's not as wide a path once you get going. I do agree passing is difficult, but I can't see me ever passing anyone except a ped.
One big benefit of a bike is you are not using calories to hold yourself up, you are sitting. This thing is a lot more work. Walking seems more efficient. ??
I only rode it mostly on a flat with very slight incline and declines. I'd rather pedal the the trike with the dog in it up hill, all 120 lbs. It seems like less work?
Always struck me as an expensive, "be seen" kind of thing. Not that it costs more than a decent bike, it's just that you get no utility for your money. Also, almost as annoying as rollerblades on the path.