Chalk (master) is an abrasive. When an abrasive is applied to anything there is friction. How hard you push down on something with friction affects the friction force. The friction force causes wear to any substance.Chalking has no consequential relationship to tip wear.
I you do not believe that, then sit in a chair and really try to wear a tip down by chalking.
You will be sitting there for a millennia.
I mean seriously, think about it.
Therefore, if you chalk lightly there is minimal wear. But if you grind chalk on hard there is significantly more wear.