People on the ground never have use for such tech. These deals are all political and the actual equipment arrives by the truckloads and sits unboxed. When people rant about ridiculous military budgets and spending it isn't about cutting soldiers' salaries but shit like this.
Apparently, training is quite expensive - actually flying planes or firing guns and missiles, especially large ones, is expensive.
I think in an ideal world they would want to just strap soldiers into 'the matrix' and train them for free in a computer. Maybe they are hoping that they can do the cheap parts of the training with AR headsets on, and see the results of what they are doing (firing a very expensive missile at a helicopter target that would burn fuel if real) in simulation?
Traditionally I understand this has been done by shouting 'bang' and pretending a helicopter exploded. Do Hollywood special effects that only they can see actually make soldiers more effective?
Huge military research budgets usually mean that this kind of spending is driven by something like a clinical trial - maybe a 3rd military research contractor trained some soldiers the normal way, and some with VR, and then compared their performance at doing 'the real task'.
This was probably then sold as a cost saving.