China probably is one of the big countries with many influences to the world. But, taking over the world with their digital currency. I don't think it can be. For, this is the world and many people are here involved. Moreover, the US will not probably allow it and there will be economic or financial wars between the two and also other developed countries around the world. And we as common person just watch and see what will happen.
Can we really think that other big and powerful countries would let themselves be controlled by China? No, it wont happen even on my dreams.They can create on what they want but it wont really be enough on control the world and we have seen on how other countries do react into certain things and in spite of involving into other works they would rather create on their own and tending not to be controlled by
any countries outthere.So the obvious answer for this question is definitely No. Digital fiat couldnt control everything, they can create but it would really be just
good locally.