not much to tell beyond the picture. Some of them are hand cranked, others include e-motors with throttle either because there's legal modes for it or maybe you're at a bikepark where usual public regs against that don't apply.
Mostly niche-builds, so custom things adapted to specific customers or small scale lines
Well, it’s primarily an accessibility bike so a person who couldn’t otherwise ride a bike can ride a bike with assistance. They offer seat belts, calf support pedals, and everything. Just because I see it as a fun ride for bike touring with my wife (not that I’ll ever have enough money to ever consider buying it) doesn’t mean the design as an accessibility bike isn’t a good design. Traditional tandems require a lot more coordination for the stoker to use. Also, traditional tandems (even really nice ones) tend to break in half because of their length and weight when under strain, which is usually the worst possible time for them to break from a safety standpoint.
Tandems for tours make a lot of sense and there were quite a few couples on tandems when I rode across the US a decade ago. Easy communication, better efficiency with wind resistance and rolling resistance compared with two bikes, and being more novel means cars wave and smile rather than run you off the road or roll coal. The only differences with this bike from that is that the wheelbase is shorter, meaning less flex so hopefully it wouldn’t snap in half, even easier communication since one person isn’t talking into someone’s lower back, and one rider has free hands.
Maybe you should go do some bicycle touring just so you can understand how much reading improves it.
That's true. A bit insensitive of me when I read it now.
Narcolepsy and stuff is straight up dangerous if you're on your own, especially in traffic, assuming you can manage a bike on your own.