I think there are a number of factors which are contributing to the dimples on the playfield.

1. The clearcoat is exceptionally thin.  I would estimate it is only 1 to 2 coats (max).  More likely one dust coat, one final.  Too thin in my opinion.
2. The game as a lot of air time / air balls
3. The timber is not as 'cured' or hard as it could be.

Its my view that the combination of 1-3 above is whats causing it.
I believe if there was a ceramic 2k clear coat (thicker), then these issues would not be visible and less of a 'golf ball' appearance.

I took some further photos of a TWDLE this morning: