One of the participants of the MSX.org reported that the Digi:Arka worked very well with Arkanoid 1 but it did not worked with Arkanoid 2.
One of the possibilities is that the rom might not have code to read the paddles, just like in the first title, and indeed it is possible to find two versions of the game with the differences pointing to corroborate this hypothesis:

But the user that reported me the problem have the original paddle controller that was bundled with the game and such controller works in both titles (Arkanoid I and II).

Further investigation is necessary...