Our alarmists here love to point out "Look, the Chinese buy our bonds and they are owning us!". At the other side of the fence the thinking in China goes that "The US can actually freeze all the bonds these Chinese Communist nouveau riche and corrupt party officials if necessary, and because they are stored in the US the Chinese can't really withdraw them."
We would be able to do that precisely once. Then our own economy would collapse because no one would buy US bonds ever again.