There have been many vehicles that have been used to gather intelligence. Not just balloons, but tons. One I recall from the 60s was a satellite that photographed Soviet sites and then dropped the film to be picked up by an aircraft with a hook. Nicely called "the Hook". Then the SR-71, but initially called the RS-71, but due to President Johnson;s dyslexia introduced as the SR-71 and thus the name stuck.
In all cases the data gathered had to get back to the gatherer some how. Now how can this China balloon get stuff back to the mainland. Simple, spread spectrum it up to a satellite and then down to the processing site. Better yet it can also communicate to agents on the ground lots of stuff.
All they need are good processing chips which thankfully we have designed and have given them! Yep, and most likely educated their technical people at our best institutions, where they were most likely supported by DoD funded research projects.
This story will make Pearl Harbor look patriotic. Remember Yamamoto was educated at Harvard. Want to see his replacement now part of the CCP, just look at the news sites of some of our top universities.