It's a shame that keyboards with programmable key images didn't get more widespread usage beyond Optimus [1]. I currently have a Corsair K95 RBG keyboard and it's programmable 18x3 keys [1] are near unusable because I can never figure out what G1 or G2 does. But if I had programmable key images...
"Widespread usage" at a $1500 price point? I don't think so. Plus, how the hell did they reach that price? The keyboard looks pretty bland: https://youtu.be/A2RhpllpDn4.
I could just add a few hundred bucks and buy a new Macbook.
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.
I think tactile feedback is still the biggest possible feature of a (real) keyboard.