The camera mirrors I've experienced so far on buses and HGVs have all been a bit crap.
They have a few big issues, like LED headlights on other vehicles strobing on the screens and not being able to deal with having both light and dark areas on the screen at the same time meaning parts of the road could disappear into darkness on the screens.
On the BYD Enviros at Lothian the nearside side repeater was within the view of the cameras which caused the screens to pulse whenever the indicator was on in low light (I drove them a lot at night).
With a normal mirror, you can physically move in the seat to change what you can see in the mirror, but with cameras they're generally fixed so you can only see what it shows.
My biggest issue with them is that mirrors work both ways while cameras only work one way.
When I'm on the road, either at work or out in the car, there's situations where I'm looking at the mirrors of other vehicles, checking to see if they're using them and whether or not they've looked and seen me and obviously with cameras you can't do that.
They're a gimmick, and the sooner they go away the better, imo.