Intend Rocksteady Magic Cranks

 I use this on an Ebike. As far as the chain hanging up there is always a safety release at the rear freewheel. Either a small breakaway zip tie to return the bike to normal, or a friction ring to drive the chain when coasting but will slip if needed. It doesn't take a lot to push the chain around when coasting. Now the loss when coasting is probably not for those trying to win a stage race by coasting further than everyone else. But on gravity bikes, and urban Ebikes this is not so much a priority, and the ability to shift without pedaling is much more useful there.On mid drive Ebike sthe front freewheel is already there. But chain management is more critical. Some users report that 1x MTB with a clutch derailleur often accept this mod well.
But a word of warning, this screwed up my shifting habits, so I had to convert my pedal bike to this also.
Going uphill there is no added loss. going downhill it has advantages. The loss is on level ground or slight downhills, and would probably add up to something over time.But only when not pedaling (you know who you are).

 One more thing. the chain guide shown in the video is not what I would use for this. If the chain does start to move out of position the friction from that type of guide will cause the wheel to push more slack into the chain. I use a recumbent toothed drive side idler that works like a derailleur pulley to catch the chain and guide it into place before it gets to the chainring. Terra Cycle makes some nice ones. Of course if your clutch derailleur is tight enough this might never happen

 good in theory, but I imagine having problems while shifting and the chain gets stuck in the derailleur. If this happens on your normal setup, you stop pedaling immediately. However, this will turn and turn and turn and will explode quickly!! Prove me wrong if i am wrong :-P

 Does it make the chain wear faster?

 That's difficult to measure, but it is always moving.

 Nice bike! CANYON SPECTRAL CFR 2022

 I want to know more!!!!!

 Friction data?