There is one thing missing. I have a child mirror on my back seat that I can see from my rear-view mirror. Kind of hard see that when the camera is pretty much looking at the outside.
Some vehicles have a camera pointed at the back seat for this reason.
Sounds like something out of price range, unless I DIY it.
When you are driving, you should be looking outside.
While that is correct, removing the ability to easily look at what is going on in rear seat will make some people uneasy.
Awareness of what's going on inside your vehicle is also of some importance.
As a parent, it is in my experience much safer to be able to flip the rear view mirror into "night mode" and have a view of what the kids are arguing about than to have to turn back even momentarily to interact with them.
When you have a kid, they try to choke on their own fingers/toys/food, throw their drink/toys, or just generally be annoying.