Are you a member of the CCP or a concerned Chinese citizen about money flowing out of China? If not, fuck off. ET has gotten a real moral bent to it recently.
It's the "underground money changers" part, plus thus use of bitcoin to export yuan which is fairly gross money laundering. Amusingly in Australia, you have to be a white male to be charged with any financial offence now - lest a non-white male is caught, and screams, racism!! LOL.
What confuses me most about the question posed in this thread is the correlation between high-income and "productivity".