That may not seem like an obvious use-case when only thinking about a piano, but since it's mapping MIDI keys to commands, I guess it should be able — or at least no very far from being able — to map ergonomic MIDI controllers to actions that are not as ergonomic with the usual keyboard / mouse / trackball / touchpad most people use.
I wrote what I believe is a similar tool but with completely different goals initially: https://github.com/Arkanosis/smhkd ; I use it with a cheap MIDI controller (namely the KORG nanoKONTROL2) and was considering using another one with motorized faders (namely the Icon Platform M).
MIDI controllers are great for all kinds of non-musical things like: - setting the volume / balance / solo / mute for speakers / multiple headsets and mixing multiple applications (eg. using pactl); - setting the zoom level / brightness for camera / webcam (eg. using v4l2-ctl) ; - setting the source / brightness for monitors (eg. using ddcutil)…
There was (still is) a very popular program called BOME Midi Translator that did something similar - think of it like AutoHotKey but specifically for midi.
Back when I made heavy use of Kontakt libraries I got frustrated at the lack of an easy way to audition the patches (of which there could be hundreds on a single sampler). To get around it, I created a Bome script so when I pressed an unused button on my midi controller it would trigger a mouse click to advance to the next patch in my DAW and then send a note-on / note-off for C4 for half a second.
Made previewing the sounds much easier.