My initial reaction to seeing one of those was, “hmm, that looks freaky and weird.” I also suspect that it’ll be doomed to commercial failure.
That said, these things seem brilliant the more I reason through it. I’d guess that nearly all the same sensations of riding a motorcycle are there with the Nikken... all of the things that make riding a motorcycle fun like punchy acceleration, open air, and leaning in corners. At the same time, doubling up the front end in this way has to be a huge boon to traction. I suspect the suspension travel on these things allows for more lean angle than I’d be comfortable with outside of a track.
It looks the rider has to work rather hard to make the bike lean. This is an unsolved problem with "leaning" tricycles. They are all top heavy, and physically exerting on hands during turns.
One way some manufacturers approached this was putting powerful hydraulics for steering, but that made the mass of a bike even higher, thus negating the benefit by far.
A good bike must have low centre of mass, and easy to turn.
At a minimum, if you build angles into the steering and suspension assembly, then when you turn the front tires lean into the turn. If you keep the center of gravity low, then you should have few problems. I’ve seen (pedal) tricycles that work that way.