In a recent article about his Sixtyforgan (an organ made from a Commodore 64 and a spring reverberation tank), Linus Akesson explained how he had used the key layout of a chromatic button accordion.

This appears to differ from the Janko layout, though they both apparently share the feature that "if you know the shape of a particular chord or scale, you can automatically play the same thing in another key just by moving your hand" (so long as you have five rows of buttons, in the accordion layout.)

There are many ways to skin this cat apparently, though as with QWERTY, established convention is hard to change.

https://www.linusakesson.net/sixtyforgan/index.php

I had not heard of it. It looks similarly motivated the harmonic table layout. https://en.wikipedia.org/wiki/Harmonic_table_note_layout

It's a bit different actually, the same keys repeat multiple times 'above' each other, in two alternating rows with half overlap. I've built a little device that you set on top of a regular piano keyboard to experiment with it but that wasn't very satisfactory. Doing a full scale conversion would be quite a job.

The harmonic table layout has multiple keys for each note too. It is different, but it seems to be borne out of a similar motivation.

Changing keys on standard keyboards just seems unnecessarily difficult.

I think I've seen that before yes. On a related note I've been learning to play accordion this past year.

Oh neat! Given the context I'm assuming a button accordion? My dad used to play one.

Actually a piano accordion, but it's been refreshing learning to play the bass buttons. They increment in 5ths along the main axis, but with an offset row also giving quick access to a major 3rd up or semitone down.

My primary instrument is piano so it's definitely involved rewiring my concept of which notes are 'close' and 'far' to match the circle of fifths. Until now I never noticed how in addition to the usual cadences, many tunes have further rising/falling sequences of 5ths in the bass.