My Nissan of nearly 4 y/o has a camera and regular mirror.
I must say the camera works fine, even a night, newer cameras might even be better.
The only 'problem' is my eyes need to adjust from distant to nearby but that's a minor issue, you get used to it.
Not surprising for me that US states have their own legislation but that does not make it useful, all following the same rules would be better.
A curious US regulation is that a rear view mirror is not allowed to give a wider view, in the rest of the world that's how it works.
With a camera this might be made adjustable.