Rear windows let you see what's behind you and keep the cabin bright, but the Polestar 4 trades glass for gadgets.

Your car's rear view mirror has historically been the most simple and straightforward safety feature, but newer mirrors may have features that require wires.

The Polestar 4's rear-view screen can be manually switched to function as a traditional mirror, but the lack of a rear window means you can't see both the rear view and the back seat at the same time.