Re: Crash Test Dummies.
This is the real crux of the matter. What is the point of "autopilot" if you can't reduce concentration by some degree? If Tesla say you require 100% attention even when on autopilot then it's effectively pointless.
It isn't so you can reduce your concentration, it is to ease the cognitive load so that more of that concentration can be applied to more important things, like paying attention to hazards.
For example, a cruise control doesn't reduce the amount of total concentration needed. It means that that part of the drivers concentration that was diverted to maintaining their speed could be diverted to other areas. More attention span is now available for monitoring other hazards. It also reduces the physical load on the body that can then cause additional distractions. On long-distance drives (most I've driven in a day is ~1400km) my foot can become cramped on the throttle maintaining a constant speed for hours on end. Getting a cramp, or sore foot, or twinge can add additional distractions. With cruise control this became much less of an issue.
As with these super-cruise control systems, if you can have it maintain the distance between you and the vehicle in front, you don't have to waste a portion of your concentration to keeping that separation - adjusting speed, etc. Now you can allocate more processing time to watching for people changing lanes unexpectedly, or entering the road unexpectedly, or animals running across the road, keeping an eye on pedestrians or other road-side hazards that may become in-road hazards (kids ducking out onto the road).