The beginning of my music store/school started when accordion was popular. After six years the accordion began to fade and the guitar became popular. My closest friend was an accordion player. He traveled form accordion to midi accordion with a sound module. His last step was to a Technics Kn1000.
Most of the accordion players who made the change to playing a keyboard had a great right hand on the keyboard. Full chords, arps, and not looking at their right hand when playing gave them a big advantage.
No disputing that piano playing gives the best advantage – for me it’s #1. The accordion players follow right behind.
John C.