I'm still wondering. As a photographer, you learn that you always want to use a focal length of 50mm+ for portraits. Otherwise, the face will look distorted. And even a non-photographer can often intuitively tell a professional photo from an iPhone selfie. The wider angle of the iPhone selfie lens changes the geometry of the face. It is very subtle. But if you took both images and overlayed them, you see that there are differences.
But, of course, I'm overlooking something here. Because if you take the same portrait at 50mm and with, say, 20mm, it's not just the focal length of the camera that differs. What also differs is the position of each camera. The 50mm camera will be positioned further away from the subject, whereas the 20mm camera has to be positioned much closer to achieve the same "shot".
So while there are differences in the geometry of the picture, these are there not because of the difference in the lenses being used, but because of the difference in the camera-subject distance.
So now I'm wondering, too, why Tesla decided against stereo vision.
It does seem, though, that they are getting that depth information through other means:
Tesla 3D point cloud: https://www.youtube.com/watch?v=YKtCD7F0Ih4
Tesla 3D depth perception: https://twitter.com/sendmcjak/status/1412607475879137280?s=6...
Tesla 3D scene reconstruction: https://twitter.com/tesla/status/1120815737654767616
Perhaps it helps that the vehicle moves? That is, after all, very close to having the same scene photographed by cameras positioned at different distances. Only that Tesla uses the same camera, but has it moving.
Also, among the front-facing cameras, the two outermost are at least a few centimeters apart. I haven't measured it, but it looks like a distance not unlike between a human's eyes [0]. Maybe that's already enough?
[0] https://www.notateslaapp.com/images/news/2022/camera-housing...