It's not just that the images will be better, it's that the sensors can get smaller. The silly bump that represents the camera on the iPhone6/Plus wouldn't be there if this existed. Google Glass could be far cheaper. Smaller SLRs, even! And everything will have far better quality than before. Truly revolutionary.
Id rather say that this means the sensors can get bigger for compact cameras and phones. Currently the only thing that limits us making pocketable full frame cameras with zoomable optics is the size of optics, not the size of sensor or other electrical components. Flat optics might make full frame camera phones even possible.
I doubt this is a big advantage because you would capture everything that is close to the sensor (dust, fingers, scratches etc.). A lens effectively applies an extreme low-pass filter to these things because they are massively out of focus.
From my own experience I can say it would be an enormous advantage when shooting in low light. At least for current sensors. Where I am living, for four months in winter have only limited hours of dim daylight and current phone sensors are pretty much useless. You are right about dust though and extra care has to be taken, but it seems as a small inconvenience to me compared to sub-acceptable noise levels.
Actually, the bump on the iPhone 6 shouldn't be there now. There are phones that are just as slim and with just as big if not bigger sensors, and are perfectly flat. The problem is Apple decided not to change the sensor this year, and used an pretty old one, which hasn't gotten anymore compact, even though the phone's body has.
Watch Apple introduce a 13 or 16MP camera this year that has no bump. Why? Because this time it will actually use a cutting edge sensor, rather than a 3 year old one.
We may also have super tiny lens free cameras that avoid these issues entirely: www.technologyreview.com/news/525731/lens-free-camera-sees-things-differently/
Chromatic aberration is one reason why you don't see many large/professional telescopes use lenses. Another is that enormous, thick, heavy lenses aren't very practical. This seems to solve both problems.
There are a lot of reasons telescopes use mirrors over lenses, only some of which this resolves. Also, will Capasso's work scale to the meters wide telescopes that you want so as to collect a lot of light?
Telescopes also require high optical efficiency, because the entire point is to capture as many photons as possible. It seems likely that any application that uses diffraction has higher-order effects that send part of the light in unwanted directions, even if there is a distinct focus.
