Virtual Reality training can be very powerful, but it's not a one-size-fits-all. The most effective use of VR is when it is used in place of real-world training that is impractical.
Without flying instructors around the world, in-person style of training can now be done in a consistently repeatable fashion. Instructors can still video-conference with their audience to prodivde the guidance and direction to make the most of the training.
People learn by doing, making mistakes, getting feedback, and iterating. That process can be dangerous in a hospital, plane, or other workplace settings. With VR we create a realistic situation that allows the participant to learn in a safe environment.
Virtual training can be used when real-world training is just too cost-prohibitive.