This thread is rather old, and you might not get reply from some of the people who posted.

SA's can be useful, but they only apply in the situation that SA calls for, so some people prefer to apply the points to the player's all over skill, or a new role.

If you already are that far, by all means finish getting the SA. If nothing else, it will make him more saleable when you no longer need him. I have have some good playmakers, but also some that collected more yellow cards than points. It depends on how well he fits into your formation & orders.

When deciding if you want to teach a player a new role or SA, make sure it fits with his current best skills and that he trains fast enough to not fall behind in Quality from teaching the extras.