The purpose is to try and put even wear on the stone and not put all the wear on one side of it. These very hard Jnats do wear as you use a progression of natural slurries on them. Synthetics wear too. I’m out of the habit of spinning synthetics because I use them for knives where I sharpen ambidextrously; right hand, right side of the knife, right side of the stone, and vice versa. I need to pay more attention when I sharpen a razor on synthetics :)

The idea is that when I flatten a stone I’m removing a lot of abrasive that was not put to good use.