The article mentions about this. Balloons at the time were too much at the mercy of winds to be useful for military. Even today, or maybe even more today, ball

The article mentions about this. Balloons at the time were too much at the mercy of winds to be useful for military. Even today, or maybe even more today, balloon flights are risky. Landing is difficult, at the best, lethal at the worst you might get burned to crisp in power cables, end up in ocean or a mountain wall. Thus, most balloons can only fly very predefined, tested, routes to avoid complications.