The issue is the charging infrastructure. Pan-National standardisation, fast v. slow charging, And who will pay for these innumerable charging points? And how does the user payment system work?
Count the number of petrol pumps you see on a typical 50 mile journey, capable of replenishing a vehicle in <5 minutes. Extrapolate that to the requirement for nationwide charging points that need (fast charge) maybe 30 minutes. How many tens/hundreds of thousands would be needed? Not forgetting the real estate needed to have vehicles sat there for ~30 minutes at each charging point.
I'm not going near any possible Army/Field aspects. I don't know enough.