Simulators are the bee's knees for learning from your mistakes. Watching the video replay of your actions can be very informative. By informative I mean that thought you have when you see yourself do something incredibly stupid without knowing it at the time.
Sim training done the right way can be very rewarding.....done the wrong way it can be soul destroying.
The best use of a Sim was in recreating situations that led to fatal crashes. The best one I recall was using the 212 Sim at FSI/Bell to re-create the conditions of a 212 crash which occurred when a crew attempted to winch a load that was way too heavy and was unable to jettison the load by cutting the cable.
We altered the CG to match that of the operator's data for the crash and then attempted to fly the aircraft in that configuration. It was most informative and demonstrated a non-standard procedure could enable the aircraft to fly away but if standard techniques ingrained in pilots were used it would not.
Sims should be teaching devices and not merely Hi-tech torture devices.