They are the shame of CC121. When I first saw it my obvious thought that I would use them for volume, cue-volume, metronome volume, and cue metronome volume. I was really chocked when I realised that you could not select the value knob with function buttons. Instead of having eight functions on the value knob they have chosen to only gave one.
If it was me I had also make the function buttons to be able to be a shift knob, and then not only for the function. Shift in the same way as CMC with precision on EQ and opened secondary function on all other knobs and buttons. I would also have implemented function long press that copied the current AI-function to the value button as an easy way to program it functions. I think it would have been some hell of useful product…