poorly implemented.

Why?

It's like they only wanted the functionality (not having to look through a dirty/rainy glass) but didn't want the streamlining.

Is there a regulatory reason for the legacy placement of the cameras and screens? At the very least, the screens could be integrated into the dashboard, so that driver's needn't take their eyes of the road as much as they do now, when looking in the mirrors. Also, with good central placement, a single camera could provide a complete view of the rear hemisphere.

physics314, there is more likely a desire to emulate traditional mirrors, with their placement at the sides, than a regulatory need. Having mirrors or displays at such locations is actually beneficial, too, as it is a good idea to have the driver aware of the areas to the sides of the vehicle, even if there is the occasional look away from the area directly in front of the vehicle.

Sounds like a very expensive way to replace a piece of glass.

Part of using an outside rear view mirror (and an inside rear view mirror) is the flexibility of moving one's head to change the angle of view. Of course, one can press buttons and rotate a digital camera, but not as quickly as a simple head movement.
I'd tear these things off and put a stalk mirror in place in an instant.

I love the concept, love the screens, and hate the ugly stalks. Now add LIDAR wireframes for rainy/foggy nights. I think passengers will like the screens, too, since they'd add vision to the person critiquing your driving, maybe shutting them up a bit. ;) I like the legacy placement, since our peripheral vision is a backup to our focused vision. It can catch those fast flying maniacs about to fly by you which didn't register in the rear view mirror scenario.

Another unnecessary glitter-gizmo to drive up the price.

@Lardo All the better for the owners to show off how rich they are.
Though it might fix the problem of people who tailgate with their high-beams on.