as far as i can tell the idea is that the rocol does a specific job. i have a very good but thin synthetic lube in it now and i have trouble getting the right speed (too fast). the rocol will slow it down and this also will help dampen chatter/noise (i think). JC Verdier wrote about this. specifically how the friction to drive the platter because of the Rocol gives cover for stylus drag so we don't hear it.
