I think a silent cyclists coming from behind you would be much harder to hear than an EV car...Just imagine riding along and having to swerve to avoid some pothole or other obstacle and next thing you know you're getting hit by some silent cyclists. This has actually happened to me many years ago when I was still new to cycling and that's one reason why I put a mirror on my bike...Lucky form me that it happened on an MUP and not on the road..