Ok.
On a liner- or framelock, I see no practical advantage, as you need to get your thumb out of the way of the blade to close the knife.
On a Compression or Axis lock, you actuate the lock release... and the blade can go home... without your digits ever crossing the path of the blade.
Safe, intuitive one-handed closing is one of the advantageous features of both of these locking systems, and the less friction on the pivot, the better it works.
A bearing pivot largely eliminates the need to compromise between friction and blade play: you can have smooth opening and closing and the "monolithic" stability of a tight pivot.
My Mini-Grip has, and will always have, some blade play to allow for easy closing. This doesn't make it unusable, but it does make the whole system feel less stable than other knives I own.
I would like to emphasize that I never suggested that all knives should run on bearings, as I don't think that's necessary.
Of the dozens of knives I own and use, only three run on bearings. Most are happily wearing washers.
Opinel? Higo No Kami? No bearings, and no washers. Both function as intended.
Where I specifically want to see the bearing "fad" (I don't think it is one) to go next:
Axis lock.
Compression lock.
