the same useless dollars China receives for it supplying...

the same useless dollars China receives for it supplying "assets" to the US....China will use to buy real assets like Australian and African mining companies as well as extending their influence and improving their technologies by manufacturing. Japan did the same by copying then European technologies like Zeis Ikon and massive shipbuilding.

Moreover they teach their people to use their savings for bying real assets like gold and silver. And using their incomes to buy houses and American rubbish like McDonalds.
So what do you like....paper money or silver and gold......seems obvious. Even Mickey Mouse knows that having an economydependent upon pieces of paper is like building a house of cards.