There were certainly military applications in the intervening time - the article only refers to the immediate 'balloon craze' period following the Mongolfiers'

There were certainly military applications in the intervening time - the article only refers to the immediate 'balloon craze' period following the Mongolfiers' initial flight, after which the hype died down and they didn't seem to immediately catch on for any practical use. But I know with certainty from family records that one of my ancestors, a British Army officer, was involved in surveying parts of India from the air in the late 19th/early 20th century. Still a far cry from the battle scenarios you are proposing, but it is reasonable to say in fact that the military did find a use for balloons eventually...