Yeah I undestand point-pressure.
But I did used to get flat spots on the odd scoring wheel (other brands not just rubi) when they jammed due to the innards not spinning freely.
Haven't used oil wheels. Not that I know of anyway. But I'd have loved some bearings!
I used to skateboard, then BMX, then mountain bike, now downhill bike, I even had bearings in a nokia scirocco that were developed by a rally team or something the sales blurb said, so I love my bearings me.