It's the one missing feature: not backlighting, no reading in the dark.
This is a prototype of a solution: a sheet of clear acrylic that fits into the screen's bevel and another opaque sheet that covers it at the bottom (you only lose the page count that way, no text) and the upper corners. The idea is to add an LED in each corner (there is enough clearance between the opaque part and the reader's faceplate) to illuminate the beveled corners of the transparent part, which should become a waveguide.
This is a prototype / proof of concept, just to see if the clear acrylic piece would actually light the screen in a useful way.
If it does, I would add mounts for the LEDs (altho... hot glueing them behind the opaque part would work too) and someplace to put the batteries.
If you have an idea on how to improve on this, it's under CC license, feel free to tinker!