Arranger players are unique to me. They are folks(like me)that are willing to spend hours programming and editing to get an arrangement the way they want it.

Most keyboard folks I know will show up with a hammered action keyboard and play with whom ever is in the group and whatever the key signature is.

I can do this on guitar/bass/mandolin. I can’t on keyboard.

In short, piano is versatile, arrangers not so much.