I don't know TBH.
I think, at the level most of us are refereeing it would be impossible to manage with CARs. Imagine, twenty minutes to go, and two or three players are all in various stages of 'sin-bin'.
You would need at least one appointed official to manage the bins with timings etc.
In principle I think it could be good for the game at higher levels that usually get three or four officials appointed, but a nightmare at our level. Although I'm not convinced it would reduce the dissent, as players will soon realise 'Hey, it's only ten minutes sitting down, not a YC and fine!'