One argument would be that once you have many vehicles operating with LIDAR, it's unclear which systems are sufficiently robust against being disrupted by interference from other systems. Same with RADAR - while this is not new technology, we've never really had a regime with potentially dozens of systems operating in close proximity.

For all Tesla's problems, the automation-via-cameras solution is the one I find myself having the least problems with: using a single, obvious input (to humans), you don't wind up in a situation where you can have multiple differently-capable systems disagreeing on what they're seeing.