It's simple - many many controllers can't send Program Change messages, or allow to send single value. If we could change CC into Program Change, then it could be possible to change synth's preset by one knob. I have few synths where it's not easy to change preset quickly (jam, for example) like Modal Craft, Skulpt, where two hands are necessary to do that (and it's quite complicated and takes too long time).
Another idea is to change single key press (for example pad) into increment/decrement program change. For example if i sent CC 1 value 1 then it will increment Program Change number, and when CC 1 value 10 then decrement Program Change (every time when pressed).
Another idea is to change single key press (for example pad) into increment/decrement program change. For example if i sent CC 1 value 1 then it will increment Program Change number, and when CC 1 value 10 then decrement Program Change (every time when pressed).