Well, apparently you can extend Emacs to have it:

Emaccordion

Control your Emacs with an accordion — or any MIDI instrument!
[…]
You can e.g. plug in a MIDI pedalboard (like one in a church organ) for modifier keys (ctrl, alt, shift); or you can define chords to trigger complex commands or macros.
[…]
The idea for the whole thing came from [dead link]. I immediately became totally convinced that a full-size chromatic button accordion with its 120 bass keys and around 64 treble keys would be the epitome of an input device for Emacs.

https://github.com/jnykopp/emaccordion