"China is trying to grow its domestic economy and rebalance it from an export and investment-based model to a consumer driven one over the next decade, and to do that the authorities want to keep as much yuan within the country as possible," said Jinny Yan, an economist with Standard Chartered bank.
I don't get this. Old wisdom says: for every buyer there is a seller. Yuans just change hands in China when bitcoins are traded at BTC China, they don't leave the country. Only bitcoins might leave the country in future, if they are cashed out in another currency later. This might lead to devaluation of the Yuan, but I doubt that the volumes are big enough to have any measurable impact.