I've idly considered solutions like this in the past as alternative mass transit solutions. Actually, my version had several (six?) parallel conveyor belts, with the outside belt moving slowly and the inside belt moving at a speed comparable to that of a light rail train. I never managed to work out a really convincing way for people to change speeds, though. Is this one the solution? I don't know, but I'm glad that they're trying it to find out.
Nowhere that I've seen yet has a figure for energy consumption. I'd be interested to know whether this could be used and extended to carry people at greater speeds for longer distances or whether that would prove extremely energy-inefficient compared to a train of some description. Theoretically I suppose that you could extend this from three belts at two different speeds to having five belts at three different speeds, but I'm not sure if the rollers for a (say) 11 km/h -> 17 km/h transfer would work as well as the ones for a 3 km/h -> 11 km/h one.
The safety concerns are interesting. I'd have thought that one way to solve them would be just to get people to sit down in a little cart because you can control carts over the rollers in a way that you cannot control feet over the rollers, but this leads to all sorts of embarkation / disembarkation / returning-the-carts problems. It also reduces the advantage that people used to travelling along a 11 km/h belt can still travel faster by walking along it at (effectively) 11 km/h + overtaking speed.
I also am uncertain about how people transfer from a handhold on a belt at one particular speed to a handhold on a belt at a faster speed - frankly, that part of the operation looks at least as fraught and dangerous as the "changing the velocity of your feet" part, and the changing height of the handhold belts looks unnecessarily exciting. (I was also never uncertain about the downside of the "slides and really long escalators" solution, if you have sufficiently efficient escalators and/or a way to convert kinetic energy back into gravitational energy.)
Despite a few petty nationalist reservations, I hope that this works, that this proves to be cost-efficient and that it can spread around the globe.