In my opinion virtual training is useful, but cannot replace actually firing real weapons and training in a real environment:

Technology plays an integral part in modern warfare, and its role is even more important for countries like South Korea, which faces constant threats from North Korea.
Yonhap
In line with changing battlefield dynamics, the South Korean military has been pushing for ways to train soldiers in simulated environments using the latest technologies, such as virtual reality (VR) and augmented reality (AR).
The Korea Military Academy has joined hands with local companies to develop VR and AR training programs for its Army cadets, which will be available on its Seoul campus later this year.
Experts say one of the key advantages of VR is the ability to immerse users in a virtual, yet safe, world, reducing costs and risks associated with battlefield training.
“Training soldiers using VR and AR content can save on the considerable budget for large-scale training and reduce risks from dangerous environments,” Kim Tae-kyu, a game professor at Kwangwoon University in Seoul, said. “It will be more beneficial when combined with real battlefield experiences.”
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