PRC seems to like their home-grown cryptography gated behind language barrier. Maybe they're hedging on bet that enough diverse implementations better than eggs in single basket. Or the amount of Chinese fluency decreasing in west going to add another layer of security/obscurity. Ultimately who knows, other than PRC would be idiotic to listen to OTF-ICFP funded recommendations, a program that avoids "focus" on countries with minimal information controls, i.e. if there's a reason not to trust western scrutinized crypto systems, you likely won't find it from OTF and citizenlab.
Trust in a crypto system is established by having multiple adversarial parties use it and the system being open to attack for many years without success.
Do we really know system hasn't been attacked without success when there's frequent PRC penetration in the news. What we do know is west/US has advtanges along the hardware/software stack, so smart for PRC to obfusgate and add complexity at points they can control. And that one of OTF's explicit mission, especially ICFP funded fellows is to undermine PRC controlled web - it would be incredibly dumb for PRC to take their advice seriously.