I love it especially as a last mile option in conjunction with buses and trains.
That or kickscooters, but they're not as compact as the onewheel or a longboard.
Fundamentally, the onewheel seems like a personal-mobility answer to the V22 Osprey: a vehicle with amazing functionality and versatility in its happy path, but is fundamentally unsafe in failure because of the basic physics of the situation.
edit: onewheel, not longboard, in the final paragraph.
Attach it to a pole or whatever.
You stay in a restaurant one or two hours at most, and you simply wouldn't go there by bike if it's raining. It's unlikely to suffer from rust.
Likewise theft only tends to happen when a bike is left in the same location for extended periods of time. Defeating a good bike lock takes a special kind of people and tools, and your bike is unlikely to be spotted then stolen in a hour or two. One solution is also to park it in a relatively discreet location, or you could go for an area full of bikes (double-edged sword; more bikes means it's lost in the sea, but also that it's a prime location for thieves. Then again if you have a functional metropolitan police they'd be watching such locations).
Personally I use an e-bike in London, I attach it everywhere outside, I never had a problem despite my bike being very cool-looking (it's a British equivalent to Super73). While London is certainly more civilized than New York City, it does have significant crime as well in certain areas.
I also have a folding e-bike which has larger and wider wheels than a scooter, which is preferable in my opinion. The problem with scooters and e-bikes, even folding ones, are that a lot of buildings will not let you take them indoors. Or most will have you use a freight elevator, which is operated manually AND has set hours that it’s run.
There’s also the difficulty of storing/locking them if you go out for dinner or some other event. Something as small as a Onewheel that you could pick up and walk with, and is small enough to store under a table, or take on a train without blocking anyone is a dream in this sort of environment.
Edit: I should also note that I’m speaking from my very NYC perspective.