Is fiat a necessary evil in times of war?

Please help me in understanding this better.

My thought process is that you can fund a war with taxes, bonds, and inflation.

If two equal countries go to war and country A issues bonds that few citizens buy and raises taxes that not enough citizens pay, and country B inflates the local currency to take advantage of the short term benefits then wins the war because it was more capitalized, wouldn't that be better than not inflating a currency?