Ok, I will agree that the term Cyber War is nonsense. But the correct term is cyber warFARE, and can do a heck of a lot more than what is let on.
First step in any war, especially modern war, is to engage is degrading the command and control communications necessary to confuse and cut off the enemy's capabilities to communicate sith troops on the ground, coordination of artillery strikes, air strikes, naval strikes, missile strikes, etc. Do we use the telegraph today? Tin cans and string? Or are the modern armies of the world using something more sophisticated?
Next degrade the capabilities to resupply. Certainly causing havoc via hacking or malware in the enemy's electrical grid, oil production, even factory assembly line processes would foot the bill for that, right?
How about satellite signal disruption? GPS trickery? Intercepting sensitive communications via malware?
This is not Cyber War, as no such thing exists. However, as a part of war, cyber warfare is becoming an increasingly important element of a military arsenal. Why drop bombs on RADAR installations when you can screw ball the RADAR network and field communications for a fraction of the cost, and at immense speed?
Yes, costs are involved in attempting to secure critical networks to assure a military can effectively communicate and track enemy movements, while the civilian factories can produce replacement weaponry, et al. As we evolve technically, costs will be incurred there too.