Originally Posted by
911slf
Unless anyone knows better: there is nothing of consequence a balloon can see that a satellite cannot see, and the US forces can likely listen in to any radio transmissions from the balloon, gaining intelligence on Chinese encryption. Yes, it's cheeky of the Chinese, but if the balloon were a serious threat it would be shot down. I suspect US can gain more than it loses by observing it and listening to its transmissions. Anyone in a position to know for sure is unlikely to post answers here.
The only advantages that I can think of is that it remains above the same area for long periods of time compared to a LEO reconnaissance satellite. Potentially, if you were interested in observing patterns of movement over relatively short periods of time (but at very high resolution) then it may have advantages. Slightly more far-fetched is the ability (compared to satellites) to conduct atmospheric sampling and to record sound. Both of these capabilities have been used in US balloon programmes in the past.
Either way, the USA has previously run a number of balloon based intelligence programmes (e.g. Genetrix) , some of which overflew China. Of course they are within their rights to shoot the thing down, but the outrage seems a little hard to justify given the history.