The bearings on Mato's boxes are part function and part marketing. The marketing part is obvious. The function part is that the shafts do turn some. I've watched my box working and sometimes the shaft turns. Probably a gear grabbing it. But since the gears don't have bearings, allowing the shaft to spin freely when grabbed by a gear, which is going to happen when allowed to spin on the shaft, it reduces the friction between the bearing and the shaft.

Not sure if that makes any sense...