While I agree with you that the rear visibility seems really bad, you eventually get used to it. Don't get me wrong -- that's not a valid excuse but in my experience I've never felt like I couldn't see what's behind me. Suggesting that's what the cameras are for is, imo, a worse excuse.

As for the head "rest", technically it's a head _restraint_ not a head _rest_. Your head shouldn't be resting against it while driving.