It's pretty different, it's a small metal bar (probably 1 inch wide 10 inch long) that you stand on with one leg, while remaining seated on the bicycle. The design is a lot more compact, so you can retrofit it to normal streets.
Sure the design is different, but the risk that the "first couple of times people usually fall off. Instant lawsuit overe there, I'm sure" looks the same to me. And yet t-bars and the like do exist in the US.
When you buy a ski pass at US ski areas you sign a huge disclaimer of liability. It's hard to imagine doing that for this kind of in-city infrastructure. Also, falling on snow is a bit different than pavement. :-)
That's a pretty strong claim. Do you have some citation for "this is a dangerous activity, participant assumes all liability" contracts being "legally meaningless?"