In order to keep my reputation of diabolo connoisseur, I asked him.
What I understood is that in PAO battles there are three rounds, the first is with bearings, the second one without, and the third one is free. So you can choose bearings or fixed axle.
But the final round has two rounds with bearings, two with fixed, and one free.
For example in the final round of PAO, he did first fixed axle (0:58 - 1:05), then bearings (1:58-2:40), then fixed axle (3:15-4:15), at 4:49 he used 1d bearing, and at 5:57 he did bearings 3D crazy combo.
So you guys were right that he uses only bearings in that video I shared on 21st of March. But apparently at least in PAO he also used fixed axle.