The SAT (Small Arms Trainer) is produced by FATS (FireArms Training Systems). That is why when the SAT is started, you see the FATS logo.
The SAT was never designed to be a marksman trainer. It was designed to teach the fundamentals of firing, and to maintain those basic skills. Basic training, such as breathing procedure, trigger pressure, but placement and so on.
To complain that the SAT doesn't let you shoot with the mag resting on the ground is just showing me that you do not understand what the SAT was designed for. You cannot teach basic principles of shooting by letting the soldier rest his mag on the ground. He'd never be able to fire in any other position!
The SAT does not teach bad habits. The SAT teaches the basics of firing a weapon. Even the PWT is designed to test the knowledge of the basics of firing, no advance skills needed to pass that!
Once again, saying that some of the best marksman out there don't need it is very true. They don't. But not all of the people in uniform nowadays can say that they are among the best marksman. As a matter of fact, I would say that the vast majority of people wearing the uniform are pretty darn bad with a weapon. It is for this vast majority that the SAT is designed to train. Not the snipers, or the designated marksmen, or even the well trained infanteer.