Late to the party, but... I'm with Paul on this one. The case for an digital accordion shares a lot with the case for an digital piano, gizmos not withstanding:
- Never needs tuning (but can be easily tuned to match another instrument that does!)
- Emulates not just one acoustic instrument, but several. My Yamaha P-515 models both a Yamaha CFX and a Bösendorfer Imperial, which really saves room in the house.
Likewise, an accordion that have different musette tunings on a whim, cassotto or not, etc., is pretty handy.
- Can be played silently, with headphones
- Orders of magnitude easier to deal with in a live, amplified situation. That's the big one for me. No mics, no feedback, no problems! This is also the reason why people like Elton John, etc., who can afford to have a real piano brought in, tuned, and miked up for a concert, still go with a digital piano in a fake piano cabinet.
I'd be totally fine with a digital accordion that was just an accordion. That's all I need one to be. Although since it's all a matter of software, that probably wouldn't change the price much.