I'm not arguing for or against either BIAB or a hardware arranger here, just comparing some ergonomic factors and wondering in part if there might be enough interested people to justify a hardware button-panel to put the direct arranger buttons close to the player's hands. I'm suspecting not, or perhaps a simple matrix-controller is enough anyway. Akai LPD8, Presonus Atom or some such. Lots of controller keyboards already have a matrix, which also suggests "no real market for such a keypad". My stage piano does not, though.

Where I think there should be be an important comparison is in the reliability/robustness area. Dedicated hardware should be dedicated to the task and not dependent upon what other software is running on a PC, and there are lots of those on most PCs. In principle dedicated hardware should be closer to "bullet proof", but in practice I'm not so sure in practice that it is. There seem to be more than a few bugs in some of these hardware arrangers. No names.

BTW, I'm not sure that comparing things like number of styles really tells the story. One could easily argue that the number of actual styles is number of base styles x number of intros x number of variations x number of endings, even before one starts selecting different styles within a single song or adding intros mid-song.

I think BIAB's strength is the ability to pre-build custom styles and structure for specific songs and assigning those by section-name, rather than having to prompt/remember that the one has, e.g., to "start with intro 2, go to style 2 for the verse, go to style 3 for the bridge, back to style two for the final eight then to ending 4". It gives the potential to have my into, my variations and my ending for each song. Conventional arrangers don't really do that, though customised styles go part way towards it.

I write here with very little actual arranger experience.

Jazz relative beginner, starting at a much older age than was helpful.
AVL:MXE Linux; Windows 11
BIAB2025 Audiophile, a bunch of other software.
Kawai MP6, Ui24R, Focusrite Saffire Pro40 and Scarletts
.