The only thing such keyboards are good for is transposing, and this one doesn't even help for all transpositions, only half of them. So you can learn something in one key, and then pretty easily play it in one of 5 other keys (note that transposing from e.g. C to D is trivial, but C to G is not). But that's about it.
It might have some minor advantages, but there are probably also disadvantages: this doesn't help you learn the different modes (minor, dorian, etc.). Instead, they might be hindered by your muscle memory.
So, for comping it can shine, but for normal music, probably a disadvantage. I certainly don't see any advantage that should make everybody switch.
So do you think if people designed a keyboard from scratch, they would come up with the same traditional layout?
It seems to me that the standard piano layout (and the standard musical notation, which is basically piano tablature) is the result of cruft being added over time rather than refactoring to better express the underlying concepts.
.. these notes seem to work well for our gloomy church chants, let's call them A, B, C, D, E, F, G
.. hmm, maybe focusing on a more cheerful mode is better, so obviously we'll tell everyone to start from C rather than A
.. it seems that some of our intervals are roughly double the other intervals, let's add in the extra notes as C#, D#, F#, G#, A#, we won't bother telling the kids what happened to E# and B# though 'cause that's too hard to explain
.. 12tet incoming, we'll just retune our existing instruments slightly
Instruments and music theory are largely based around 12TET nowadays, but it seems like it's tacked on top of something else.
> So do you think if people designed a keyboard from scratch, they would come up with the same traditional layout?
That depends on the constraints. Today's keyboard is a good compromise even today. You can compromise different things, but a full micro-tonal keyboard isn't enough better as to be worth it for most things and once you agree that you must compromise the only question is what. A 9:8 or 10:9 major second are both of rare use and so you probably just agree to get rid of them. The only hard part is 3rds, would you accept how bad they sound in a the current system (in which case a true 5th and a equal tempered 5th are close enough), or try to divide the thirds somehow.
It might have some minor advantages, but there are probably also disadvantages: this doesn't help you learn the different modes (minor, dorian, etc.). Instead, they might be hindered by your muscle memory.
So, for comping it can shine, but for normal music, probably a disadvantage. I certainly don't see any advantage that should make everybody switch.