It’s a common talking point, I doubt that comment was sarcastic. Musk has said that he thinks Lidar is useless because humans operate vehicles with just vision, which of course is an unfair comparison since humans have intelligence to help them.

This has always been a ridiculous argument. Human eyes have a much higher contrast ratio than commercial cameras, and have built-in stereoscopic capabilities with some degree of rangefinding thanks to the fact that they are quickly adjustable. Normal cameras have none of that.

It was not sarcastic. I'm not really sure what you're arguing. It's obvious that vision-only would be more advanced than using lidars. Lidars are expensive and take space, so that's why they're trying to use cameras only.

And it's quite obvious that there are at least some situations in which vision will not work whatsoever - e.g. dense fog. I personally would quite like my autonomous vehicle to operate happily through dense fog. If you're happy to pull over to the side of the road and wait it out, be my guest.

Having multiple orthogonal subsets of the electromagnetic spectrum at your disposal provides redundancy and diversity - two features that simply CANNOT be accommodated with a single class of sensor, not matter how advanced it may be.

Yeah, that's true. Teslas have a front-facing long range radar and multiple ultrasonic sensors around the car for close range detection. Like most modern cars. But they are there just to avoid hitting anything, but can't be used alone for driving autonomously.