There really is no such thing as a free lunch in economics. Countries with massive budget deficits should be cutting expenditure, and not borrowing more.
Buying up your own debt is no more useful than swapping one credit card for another. It is nothing close to sound finance. It is the last act of desperation when there is nothing else left to do.
You flood an indebted banking system with money, you get inflation and the relative value of fixed debt goes down.
But this is not a magic bullet. You get inflation back in the system, and anybody on a fixed income becomes poorer as prices rise. If you are an investor, your dollars become worth less, and eventually worthless.
That is why the gold price jumped yesterday. And it is going to go a lot higher as investors reach for a safe haven. Beware being left sat on cash when you should be owning gold and silver as a hedge against desperate actions by the central banks.