Why not use the official media though? If China wants to inspire confidence in her citizen internet leak is NOT the way to go. How do you expect your average citizen to tell genuine info apart from Fengqing wetdreams?
China does this often, and it's not for internal consumption. Releasing info this way achieves deterrent objectives, as foreign military intel can tell what's genuine info, but it also affords the Chinese government plausible deniability diplomatically since military intel generally can't release to the public their methods for ascertaining the veracity of these unofficial releases.