Virtual Reality is a very peculiar technology. It will allow people to be virtually transported to another location and be totally immersed into that environment. For training, this immersion is very important and can be explained by the Cone of Learning (see picture).
The Cone of Learning visually tells the story of how people remember things. If you just read something, you will only remember a fraction of the information after a few weeks (about 10%). If you actively do something (for example drill a hole in a wall), you will typically remember about 90% of this activity.
Virtual Reality is so powerful because it works on the bottom of the pyramid. Indeed, the immersion means that you are experiencing the activity and potentially even are interacting with elements in this environment.
As such, Virtual Reality is a great tool to be used in training personnel. You will be able to massively improve retention as well as engagement using these new technologies.