The only difference is that China obtained their dollars through exporting produce to the USA, in a sense contributing to the wealth of the American population, whereas the federal reserve obtained their dollars through printing, thus debasing the currency and reducing the wealth of their own people.

Both bonds sold represent a liability.

P.S.: I'm a non-smoker and believe that there is a difference between the issue of money (no interest due) and controlling the issue of the same (with interest due).