Not really, and valve has also banned these at the macro level.
They just allow you to set them up such that when you start strafing (ie moving) in an opposite direction by pushing an opposing key (ie you're holding down "move right" -> "d", but now start holding down "move left" -> "a") that there is no overlap between the "d" and "a" being held down, as some games (CS) punish having both down at the same time. Valves idea is that minimising the time gap as you switch directions, while never having the two keys overlap as pressed, is an important learned skill that novices should not be able to do as cleanly as pros, and have said that keyboards that support this seamless transition will be banned.
They just allow you to set them up such that when you start strafing (ie moving) in an opposite direction by pushing an opposing key (ie you're holding down "move right" -> "d", but now start holding down "move left" -> "a") that there is no overlap between the "d" and "a" being held down, as some games (CS) punish having both down at the same time. Valves idea is that minimising the time gap as you switch directions, while never having the two keys overlap as pressed, is an important learned skill that novices should not be able to do as cleanly as pros, and have said that keyboards that support this seamless transition will be banned.