Use case when using it as a keyboard is fairly clear actually, they become left Shift, Fn, and Ctrl and Alt.
Ah, sure! :~)
What did you dislike about them, the positioning or how they felt to press? IIUC the latter will be different once the buttons actually connect with the switches on the PCB.
Yes, they did not work well. Might be much better when the Pyra is complete.