Backup cameras are a 100% benefit. I can't believe that anyone would complain about one, just don't look at it if it bothers you? At any rate, it's an additional safety feature and any good driver will also use the mirrors and their eye sight to see where they are going, not just the camera. Backup cameras can absolutely save the life of a small child or animal behind your rear and could have prevented countless tragedies since the invention of the automobile.
Some of the other features can be annoying but they are all able to be cancelled in the new cars I've rented and the one I now own. The worst by far was the *active lane monitor* or whatever they call it on a Hyundai. I pulled onto an entrance lane of a highway with a big white strip painted on the right, (but still with a car width on the other side of it at least), when I veered over the line, the steering wheel started fighting me and trying to drive the car itself. That was a little unsettling.
I pulled over and disabled all of that **** immediately. As for door locks and trunk locks, every Manufacturer has their own way of handling that. You just need to learn your own car...no different than it ever was.