I only back into spaces if absolutely necessary. I can't recall in 50 years of driving ever having any close encounters when backing out of a space and I always drive small low-riding cars, which makes it more difficult to see around the giant SUV's and trucks (of course even pulling out would still present this challenge). Proceeding slowly, repeatedly checking both directions and being ready to break instantly, should prevent any accidents or, if there is one, it should be very minimal. I have a back-up camera but rarely use it other than as a guide to make sure I'm centered backing out of my very narrow garage and would never rely on it as my primary guide to backing out or a parking space in a lot.
The thing I don't like about people backing in to a space is that they don't seem to be very good at it. The majority of them end up crooked or with one or more wheels on or over the line. Of course they could take the time to fix it, but most don't apparently.
Another thing I often see is that people exiting a space, either by backing or pulling, seem to assume they have the right of way and all other cars and pedestrians should yield to them. And they get angry if you don't.