It’s a fairly common practice to have a localized geodetic datum defined for a country. WGS84 isn’t necessarily sufficiently accurate for all purposes, continen

It’s a fairly common practice to have a localized geodetic datum defined for a country. WGS84 isn’t necessarily sufficiently accurate for all purposes, continental plates drift, the ellipsoid can be adjusted to local circumstances and so forth. When you want to compare very precise measurements over time, WGS84 is too imprecise. Most of course avoid obfuscating their own maps, it seems like that is a result of 2002 legislation coming out of Beijing. There’s a long history of doing this, civilian Soviet maps often simply omitted a grid. While mapping an adversary is comparatively trivial and cheap today, this sort of thinking wasn’t entirely unreasonable back during the cold war, when maps truly were hard to develop from afar (there’s a brilliant and beautiful book on this subject called “The Red Atlas”). There’s a saying that generals often fight the last war, maybe that’s why China chose to obfuscate their maps well into the satellite and GPS era.