Could be filled with bioweapons that would only be released if shot down.....
Then China could claim we did it to ourselves.......
As I see it the problem with a bioweapon (living ones at least) UV light would kill it before it could do any damage.
And besides. The Chinese released a bioweapon using commercial air travel with Kung Flu. Why bother with a balloon?
It is the Biden cash delivery balloon force. They aren’t exactly learning anything new with a balloon that the Chinese don’t already know from satellite. This is just probing our weakness and response. And likely, I believe, launched from Chinese submarines. No way these showed up floating all the way from China undetected. (Assuming anything we are told is true)