[ramblenode]

Kind of cool, but I'm trying to think of what this offers over just eye candy. Maybe it could aid key combinations, e.g. pressing the meta key illuminates other parts of the keyboard for completion. Finger DDR, whack-a-mole?

As others have mentioned, looking at the keyboard is generally something to be avoided. The premise for this is sort of a workflow antipattern.

[arkitaip]

It works best when you have a lot of additional blank function keys, like the Corsair K95 has, that you can both program and assign images to.