I have less information about abroad but i must say something that we have to reason collectively,
Out of
195 countries in the world i know too well that most of the population (country's) are solely depending on USD, EURO, POUNDS, YUAN for major trade. I mean before anyone could trade among these 195 you need any of those currency to be able to travel across, and if only 6 countries decides to breakout from USD how do you think it will affect the US dollar?
There will be no much effects
Right now there may be no effect or significant effect but if other countries begin to buy into the idea one at a time, it may be troubling for the USD. These kinds of things take time. It doesn't just happen overnight. Alexander did not conquer half of the world in one day, Rome did not rule most of the world in one day, and Britain did not colonize their colonies in one day. Even America did not become a world power overnight.
This is just the beginning of the plot between Russia and China. China has been looking for ways to make the yuan a federal reserve for a while now.
Personally, I don't believe in their idea. China is not a country I can trust. They're no different from the US. They're both looking for ways to make their countries and their economy stronger.
Another reason why I'll always pick the USD over the yuan is that I'll choose capitalism over socialism anytime, any day.