It’s camera pass-through, so while it is the same idea as hololens (overlaying windows on reality). The hololens would actually be a safer thing to wear while driving, given it fully transparent. There are not screens blocking your vision with camera feeds overlayed on top.
Elon has literally said exactly this so many times. I think it is probably possible to make a car drive with just vision, but you make the task monumentally harder by not having things that ground you in reality, ie. lidar.