Whether China's yuan should be freely convertible to other currencies is something the PRC has struggled with for years. A freely convertible yuan would increase China's influence on the world financial system, but it would also increase the influence of the world financial system on China. And it would require much easing, if not elimination, of China's exchange controls.
A decade ago, a freely convertible yuan was seen as likely. But China has backed off from that. Xi Jinping's "China 2025" is about autarky - reducing China's dependency on the rest of the world.
So, the yuan as a world currency isn't really happening yet.
Euros, though...