While this is really cool and should be an option in all painting programs, a part of me wonders if this complicates the learning process of painting?

After all, mixing paint colors is something you have to learn because it's not very intuitive.

Almost everywhere else in life, when you mix A and B, you expect a linear transition to happen. By adding salt to water, you are increasing its saltiness, it's not expected that at some point, the water becomes sour before it becomes salty again.