Well I use the rear view mirror, both door mirrors and look over my shoulder when reversing so a camera isn’t essential.
However having one adds an extra level of safety. Try getting a good old fashioned dustbin and placing it a couple of feet from your back bumper. Sit in the driver’s seat and use all the options mentioned above to check for obstructions. Can’t see it can you? Admittedly not much chance of anyone standing a dustbin behind your car and it can’t move by itself.
Got rear sensors on the car too. They started bleeping but I nudged the bin.
No damage done but the trouble is I had at the time plants sort of overhanging the driveway plus the hedge needed trimming. When that happens I normally have to trim at least the narrowest part of the drive as it sets the sensors off.
A few times I’ve actually got out of the car (daily driver) to check there wasn’t anything at the rear, just plants overhanging. In this situation apart from the obvious, trim my bushes😄 it would be good to have a camera back there.
I always drive out in the NC, reverse in so I can at least see if there’s an obstruction better that way.