This question is not relative to performing its in the setup and work in a studio.
Most if not all studio software have mouse supporrt . Why not the new Yamaha Arrangers ?
I have an Sx 900 attched to an external minitor.
I find myself leaning over the internal display ( not easy to see from some angles) with an out stretched arm picking at a small touch screen
while i have large easy to read minitor in front of me.
It would seem to me that a mouse device would improve the ergonmics significantly.