I am an accordion enthusiast for sure and anything new in that arena is excitement for me, but the digital accordion has been around for a few decades, and 'electronic' accordions go farther back than midi.
There are many many companies whose circuitry has been added into the accordions to produce the same capabilities that are found in the newest Roland models.
I think that the biggest difference, or enhancement, that seems to be getting the attention with the Roland accordion, is its ability to control expression thru the bellows more than the other brands.
I have not seen or tried the Roland models.
Keyboard mag tested and gave the Roland accordion very good marks, but thru word of mouth from pro accordionists that I've talked with, they don't plan on changing over to Roland from what they already have.
I personally am very happy though, that a major name, high-quality company like Roland continues to bring modern technology to an instrument that unfairly gets boxed into a corner, associated with a few old ethnic styles. As an arranger/controller, its got massive capabilities, but very few artists are out there demonstrating it.