Japan was trying to start forest fires. The target area was basically the western US, didn’t need much accuracy. They didn’t have the range to reach the US with heavier-than-air stuff.

Balloons give limited control over target. If you can control height and know the winds, maybe you get some control.

But in general, whatever you’re launching probably has to be pretty tolerant of poor accuracy.

They buy you loiter time, but the purpose of this isn’t reconnaissance.

If you drop it, to decouple it from the balloon, maybe air-deployed mines. I can imagine having a collection of mines, having a GPS receiver on the thing, and dropping some whenever the thing crosses a designated area, like the road network in Russia. Enough of those could probably disrupt logistics.

I think that there’s probably more bang for the buck with drones, though.

EDIT: Maybe you could use the balloon as a radio relay and have a detachable drone or drones. Just use the balloon to get the drones into the right approximate area. That’d be like a super-low-end aerial platform capable of using PGMs.

I’m an idiot.