Great video Russ, and great comments and questions.
Some additional important topics...
(1) Settling In: It is obvious that the ball surface changes with use. But where a coverstock settles in with use depends upon the chemistry of the coverstock (what it's made of), what surface you start with (e.g. grit), and what surface you are bowling on.
For example, if you want your coverstock to hold a 2000 grit surface, you will need to start much rougher, then break it in. You use the scanner to see which starting grit ends up producing a more stable final number with use.
This allow the shop owner to 'tune in' a coverstock for a particular bowler in a particular set of conditions. Every 30 games or so, the bowler brings the ball back in for resurfacing, then breaks it in a game or two to get it back into steady state.
(2) More Consistent Reaction: Once you know which surface is working best for a bowler (say he likes his reaction right now...you can use the scanner to measure the roughness of his track), you can resurface the ball so the ENTIRE surface of the ball has this roughness.
This makes the bowler and the ball reaction more consistent, because the ball doesn't have to be in precisely the same part of the track every time. It increases his margin for error...giving him higher average scores.
(3) Preparing Arsenals. I had a pro bring me his arsenal once before a tournament. All his equipment had essentially the same surface, despite the fact that they started out with supposedly different grits. That is no arsenal! Without the scanner, you have no way to confirm that you are taking different surfaces to the lanes. You also don't know which coverstocks change faster/slower, and where to start them in order to end up where you want to be for the tournament.