Why do governments budget or limit spending at all, SirFredFGeorge?
In normal times, printing money is inflationary, so it's bad as it just makes your country more and more uncompetitive with the rest of the world, makes everything you buy in more expensive.
So inflation is bad for your country. Running permanent deficits that aren't investments that provide a return (say simply paying every worker more money) will lead to inflation. In crisis situations, it's a bit different, letting businesses fail will destroy previous investment - imagine say a coffee shop closing, the coffee machine, the chairs, everything will likely be junked, destroying good assets, not a huge deal on a coffee shop, but imagine that's a widget maker. So here even paying the wages and helping out the company is actually an investment in stopping that business failing and destroy the assets (both the physical things, but also the knowledge of the workers).
So you can borrow lots from yourself to invest, but doing it not to invest causes inflation, which impacts your ability to buy stuff from overseas.