So Openstreetmap must be illegal in China! And indeed it is: https://wiki.openstreetmap.org/wiki/China Of course that doesn't stop people from mapping every bench in China https://www.openstreetmap.org/search?query=China#map=3/33.99...
In any case, according to Wikipedia, open-source code is available to convert between WGS-84 and the obfuscated GJC-02 coordinates.
Since technology seems to have caught up with it, is there any advantage (military or otherwise) for China to persist with obfuscation? Much like the US gave up on GPS "selective availability" years ago, there would seem now days to be more economic advantage to ditching obfuscation than there is security advantage of keeping it. Is not as if the missiles of China's enemies are going to get confused by China's obfuscated coordinates.
Is it just because of inertia that GJC-02 still exists?