Film has an angular sensitivity function referred to as "cosine response". This is typically a response factor of 1 at 0 degrees angle of incidence and 0 at 90 degree angle of incidence. Digital sensors have a very narrow cosine response, so curving the edges of the sensor in this case will reduce the angle of incidence and therefore improve sensitivity. Vignetting is an example of cosine response. Wide angle lenses with short back element to film distances have very high angles of incidence to the film plane in the corners.
Long story short, this should be a major improvement for older glass lenses that basically project their images on a spherical surface, but "got away with it" since film's cosine response is much better than digital sensors.
I also believe this is indicative of the "flattening" that people see with modern lenses versus old glass. I for one ascribe to the theory - it's subtle, but there, particularly at wide apertures. Remember your eye's sensor is on the back of a sphere, not a flat plane.
It'll be expensive, but probably worth it. Time will tell.
One thing's for sure, technology advances, which is sometimes good to see, when it's put to constructive use.