This bike uses strings instead of a chain

A chain works perfectly fine. Why change it? It's like trying to change a wheel shape.

Does it really work?

Νο

It seems very complicated, but the gear change is interesting. Seems like commuter bike targeted, which these days probably needs e-bike assist available. There might be room in the hub for that. I'm not sure how the rotary motion is better than just having up-down.