I think they’d be functionally useless for my daily driver, but a keyboard that shows contextual hot keys to an app I’m learning (photoshop, blender, etc) would be a game changer.
I want them in arcade buttons to show the mapping for the currently playing emulator / game. You can get circular 0.71 inch LCD screens for under $1.50 (160x160) - which will fit all sizes of arcade buttons, but for some reason no one built this yet... :)