I always thought the biggest benefit from radar was the ability to measure relative speed at a distance, say 50-300 yards. If you don't think radar is better at that task, just ask the officer next time you get pulled over for speeding, I know my binocular vision is challenged estimating relative speed at longer distances. I'm very dependent on break lights. but they don't always work.
I trust that Tesla's solution using just vision is real, I just don't know how they do it. Do they measure distance by having binocular vision with wider separation of the cameras, measure changes in focal length of the cameras, measure changes in relative size of the Images, etc.? What other options are availabe?