I mean yeah, but it is a friggin ton heavy object moving at high speed controlled by a computer. Having another kind of sensor system to cross-check might be the reasonable thing to have, even if you happen to make it work well in 99% of the cases just with optics — the issue is that the other 1% kill people.

Your optical system can be good as heck till a bug hits it directly on the lense coving an important frontal area and make it behave weirdly.