As someone who can only afford cars that are 10+ years old, i've never owened a car with a backup camera. And in a way-- good. That part of my brain, let it continue to develop. I am much better at "feeling out" where a car is than my friends who rely on back up cameras.
I understand your skepticism 100%, but I suspect you might change your mind if you, say, rented a car with it for a week. It's definitely a net positive for safety, and it probably costs the auto maker less than the seat belts (literally).
Being good at driving doesn’t fix the huge blind spot you have behind your car
unless you're Yoda or Luke Skywalker, you're not "feeling" a 4-year old walking behind you in your blind spot.
I used to be ornery about this but having a camera mounted on the back of the trunk that can see all the way down both ways of the aisle is actually a huge boon when backing out of a spot. Especially if I am parked next to something that is taller than my golf, which is most vehicles.
Backup camera are insanely nice. Modern cars give you things that even great awareness won't give you. The bird's eye view you get with multiple cameras is sheer magic.
Sure, and you may as well walk around with a blindfold on to develop your "spidey" senses too.