No one can be sure if SA is good or is not good,i remember i lost a match 1-0, the goal was scored from a ck and i had 4 players with aerial defender SA..that thing that sometimes different SA is blinking has no importance to me,let's not forget that we are watching a simulation, like sometimes, if we watch a match from 2 different devices, when a goal is scored on one device is showing that the goal was scored from a ck and on the other is showing that the goal was scored from normal play.
I also belive that SA are just cosmetic.