What does "high-fidelity" simulation actually mean, and why does realism matter?

“High-fidelity simulation replicates the look, feel, and physiological behavior of a real patient, for example, pulsatile arterial bleeding that stops only when hemorrhage control is performed correctly, dynamic vital signs, realistic airway anatomy, and tissue that responds like the human body. Research consistently shows that the closer training is to reality, the better skills transfer under stress.”