In the USA you really have to be in the right place and with the right weather or gear to make use of an ebike or bicycle for practical transportation. It's mostly major cities, college towns, coastal areas, and the rare rural walkable communities that are most accommodating.
I think this is spot on the money. Things just have to be close enough to make it reasonable, with enough "negative infrastructure" to make it more reasonable than just driving. For example, where I live, I have a U-Shaped profile commute by bicycle. Down a hill, flat, then up a hill. However, my equivalent car commute is a huge pain in the ass; terrible traffic, slow surface streets, somewhat high risk and tons of roadworks - the infrastructure makes it miserable. No parking at your destination, such as what I often find with Edmonds, WA, is another example of negative infrastructure.
I don't think these will do that well, because they're not quite competing in the space they need to be. Objectively speaking unless they're modified for the US market they're a Class 1 eBike that can't be put inside another vehicle easily, and also wouldn't be accepted on bicycle trails. You're looking at a product seeking a market, not a market seeking a product.
Places they'd do well are the same places they'd do well to legalize using golf carts to do the same task, because golf carts have roughly the same speed limit and the same "you can't put this vehicle inside another vehicle" mentality. So if you look around and think, "I could easily use a golf cart to do all my tasks" then this is a vehicle for you. As an example of why this is competing in the wrong segment even though it would meet the golf cart statement is again Edmonds, WA where there's no parking nearby - if I had a Lectric bicycle, that opens the possibility of me parking 2+ miles away, bicycling in, doing my activities, then bicycling back to the car. You can't do that with the eCub, unless you actually live in Edmonds, at which point you're rich enough that you're buying a CT125.
It also doesn't solve the market segments of last mile delivery, food delivery, or courier work, which are all spaces the existing products compete in. MAYBE it's a reasonable pit bike or CT90 alternative.
The one thing they've nailed is the price. It's absolutely spot on for where it needs to be. If the charging and accessories stories (lighting, built in storage, etc.) are all in place it could be a good package deal for that price.