I can see the logic there - but I can also see a downside. Humans can only look at one thing at a time, and everything around it blurs out. If you had 4 camera feeds streaming, you could only focus on 1 at a time, moving your eyes around to each of them. You'd likely focus on the rear camera if it's backing up, but you might catch some movement out of the corner of your eye on the left repeater camera, so you stop looking at the back camera and focus on the left repeater. You can see where this is going. Now - take all that into consideration, and you're not paying ANY attention to what's happening with the actual car, you're just focusing on the feeds on your phone. You don't see that [insert object here] or the car turning into your parking lane (at least until the camera feeds spot it), so you may miss important information.