According to Roland website, the left and right keyboards are velocity sensitive but I did not see anything about after-touch though.
These digital accordions have approximately 30 accordion voices and about the same number of orchestral voices.
They do not have styles or auto accompaniment built in.
Most of the midi/digital accordion players that I see or know, use sound modules like Ketron, Solton, Orla, etc. to get all of the voices and the rhythm/styles that they need.
Thats more dollars to spend, unless you plan on hooking up to your existing keyboard.