Backup cams are mandated now, so it's good thing they didn't rely on this sample size of 1. Small children and pets everywhere will be less likely to get run over as a result.
The company puts those features in there because the market is telling them to. Bad UX is orthogonal to that fact.
I'm not really opposed to reversing cameras by themselves, but a) it takes up dashboard real estate for a feature I don't really use, and b) as soon as you put a screen on the dashboard, the company is going to want to put all sorts of annoying "features" into it.