I'm just a dumb bunny. I'll admit it. I'm a contractor, not an engineer. My old man has used and abused some form or fashion of Buck 110 (I think he's on his 3rd in 40ish years) doing a very dirty job. Can you believe it....NO washers and NO bearings
But being a brash young man (well, youngish) my EDC is generally some sort of ZT sporting some of those newfangled BBs. Cutting, mild digging, etc...no issues at all. No failure, no difficulty cleaning, and no jamming of the action. It just works. I've never given it a care nor even a thought. I just used my knife.
Now, I may be a dumb bunny, but I have also been known to be crazy like a fox. When I'm on the job and I need to really cut or pry into something hard-core I reach past my folder to a 4-5" fixed blade. Never had the bearings NOR the washers fail on one of those
I think academic discussion on the PB v. Bearings is informative and entertaining, but I also think it's a non-issue. Both are proven to be strong enough for what a folding knife is supposed to do for my needs.