It does not change anything. The government has to pay off its debt. The only way the government can pay off its debt is to steal from the taxpayer.
Let’s make it easy. Let’s say Tim, being an idiot, loaned the $100 to the government. The government then gave it back to Tim and he spends it on a worthless bridge. Tim now does not have the $100 anymore. Now, the government has to pay back its debt to Tim. So, being that it is the government, it taxes, for ease of argument, whomever it is that now has the $100 to give it back to Tim. So now, someone in the economy has $100 less and we have a worthless bridge to show for it.
So, Tim gets the $100 back and spends it on the worthless bridge. He doesn’t have it anymore. Where’s the money now? It didn’t dissapear. It wasn’t credit created out of thin air that gets extinguished. The assumption here is that the money supply is fixed and we’re talking about real money. When Tim spent the $100 on the bridge someone else receives the money from Tim. Maybe it goes to a salary of the bridge worker. Maybe the salary of a truck driver who uses it to buy groceries. The grocer loans the money back to the gov’t or the gov’t taxes it back. The money doesn’t dissapear. It is possible that the gov’t is the main spender of money in the economy. All money is circulated throughout the economy but doing so passes through the gov’t chute. The gov’t is the “pump” who pushes the money through the economy. While this may not be long term realistic or sustainable, as long as the money is not extinguished or destroyed it does end up in the hands of someone else in the economy - who can directly or indirectly hand it back to the gov’t. Or the gov’t can tax/confiscate it back. Or the gov’t can confiscate it by counterfitting more money. This is why it’s considered “stimulus”. As in a ripple effect, who ever eventually receives the money down stream could possible lend it back to the gov’t for the gov’t to dictate once again where it gets spent.
Unfortunately this scheme will only do harm, not good. It redistributes the wealth of the economy and distorts the economies price structure and structure of production. Only to unwind once again when the gov’t turns off the money pump and the economy decides once again what products and services it wants - once it is off the life support of gov’t. Then we have another recession to correct the structure of production once again.