One effect is China’s Central Bank no longer needs to buy US dollars to kepp the Yuan undervalued. There goes a nmajor purchaser of US treasuries. In a sense, China is like Visa sending you a letter saying your line has been frozen.
China’s PPP GDP is 9 Trillion USD
China’s Nominal GDP is only 5 Trillion USD.
Due to currency peg to the Dollar, the Yuan is considered to be about 30-50 percent below it’s actual market value.
So if the Chinese were to let their currency float tomorrow, China’s nominal GDP would rise to about 7 Trillion USD per year immediately.