Sorry in advance for the book LOL
The issue with describing using spin for position as it's own thing, is that it's only part of playing position and is actually a sub-category of angle and speed. When I try to break down the theory of playing pool past making a single ball I describe the game as just being angles and speed when plotting position, add in making the ball and that is it, 3 steps to learning to move the cueball around, winning games, and understanding pool, or "pool vision" as I like to call it. That is as easy as I figured out being able to have anyone grasp the concept of playing pool as a whole vs just one shot at a time. You can say that playing position is using a formula to arrive at a final cueball position.
Our formula for position and really the core of the game would be Angle + Speed +-(Spin) = Position, so if we want say position 230 but our angle and speed will only go to 100 each (for whatever reasons we pick), we need to use 30 Spin to adjust that. Or say we need position 30 but our Angle and Speed will add up to 40 due to just too much cut angle, now we need to apply some negative Spin factor with inside spin. Spin is in brackets since it's an optional variable, we don't NEED it for the formula like we need angle and speed but we do use it in the case where our Angle and Speed don't add up to Position either by our choice to use less or more of either or by the fact that the physical reality of the table won't allow us to get there without help of Spin.
Spin is really just something that changes angle and speed, so you can use that as part of those two factors. You can have many position targets with the same angle by varying the speed, or you can have similar results with the same speed by changing the angle. The spin on the ball affects one or both of those things, but then acts as a negative to being able to pocket the ball (due to deflection or needing to hit harder and thus loose accuracy on the hit).
A pool shot is a balance of 4 things (from the most simple way I can put it at least), and you can make a pretty decent diagram where you have 4 points of variance, speed, angle, distance to pocket and spin, as you add or subtract any of those, you will make up a complete shot difficulty diagram, similar to the table difficulty spreadsheet we have. The area of the interior of the plotted points is the theoretical difficulty factor of the shot, with more area = harder shot.
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Note that we need to simplify things a bit for most players under say a C+ level, so rails condition, pocket size, table size, humidity, dirt, etc... are not in the picture at this simple stage. But even if we add in all those, really the things they affect are the basic angle and speed of the shot, we just need to adjust the final resting place of the cueball we want when dealing with the many variables we run into as advanced players. But for simple things, say teaching a robot to place the cueball HERE on a theoretical perfect table, these should be enough.
