I think it’s telling that only pianists get a system like this… Perhaps a subtle dig at how many arranger players don’t seem to put much emphasis on dynamics, and perhaps come from an organ background where the dynamics come from the swell pedal..!

On the other hand, there’s no reason something like this couldn’t be triggered by how far down an expression pedal is pressed.

But yes, I kind of figured this system really only works with styles deliberately written that way for it, with probably much less variation from first to last, as you say.

It’s a great idea, but like so many things remaining to be done, only those with fairly decent playing skills will benefit much as it relies on a foundation of decent piano technique to be able to summon it at will. And, like so much about arrangers, playing well in the first place is the key to getting the arranger to sound better, no matter what you use…