This is really the killer feature as I see it. Instead of external light making screen content harder to see, it actually makes it more visible. I think there are plenty of uses for this technology.
Current displays are a huge power hog because they have to compete with/outshine ambient light. With this technology, we use ambient light to make the display content visible, instead of trying to outshine it by cranking up the backlight.
I wish E-Ink would get more attention because of this. Forget power consumption as the killer feature...it would look more natural and you wouldn't be shining a bright light in your face all the time.
I'm pretty sure a generation from now kids will not be able to comprehend that we once used additive light displays. It's really a poor reflection on the way markets work that the "good enough" of backlit displays has stifled the correct way to do it for so long.