They are cheap, but range and resolution are terrible. More comparable are the radar units for the "car in your blindspot" lights in mirrors (not really comparable to lidar at all, just vastly better than sonar.) Tesla dropped those too, with a claim that they were a lot flakier than their optical system (which I don't dispute - the material the published about it was pretty convincing - though mostly it gave the impression that Tesla's radar implementation was terrible, and that optical modeling beating it wasn't as impressive as it might sound.)
Even if we take this at face value, and assume that the camera is better, the implementation is horrible. Don’t force the driver to look at the screen in the middle, put red lights in the mirrors instead.
But as usual Tesla likes to be different for the shake of being different even if this makes the car worse