Presumably, being a balloon, then like any other balloon it just went where the wind took it?
Balloon pilots are able to use varying winds at different altitudes for directional control (clearly within limitations and not an exact science) and even high-up using Jetstream’s, so for me, the balloons incursion of US airspace was no accident.
Whether it be public/press or government/DoD response to this overfly, there can be no doubt, China will have learnt plenty from this episode.