I think that with regard to the bellows, you cannot properly compare to what an acoustic accordion does. With an acoustic accordion, the sound rides on the breath of the accordion. With a Roland, the volume is adjusted according to the pressure on the bellows.Hah yeah I practiced with them off for a few weeks but going forward I’ve got them on. Helps to have bellows curve set to 4 (xtra lite) and the bellows to the tightest imo, not sure how you have it set.
The result is not comparable, the tactile connection is not comparable. Still, I think it makes sense working with the bellows on a Roland. Whether or not you consider it a practice instrument or the final target, it adds one dimension to your play.