What’s the innovative thing about public debt?

Ok, so let me see if I got it correct. Normal governments do day to day stuff using taxes (or at least, should be). And sometimes there's stuff out there that requires massive levels of cash, right now. Maybe its war, maybe its a natural disaster, or maybe you need infrastructure projects.

You can either do it right now, or you can do it later on, but stuff like this tends to be really time-sensitive. So you either massively raise taxes, borrow money from a merchant/ noble, or you debase the coinage. These all cause problems on their own.

Public debt is basically the equivalent of borrowing money, but spread out to a larger and more distributed population instead of one or two richer bankers who might use it as leverage or just refuse to lend.

Did I get it correct? And if so, what's so innovative about it?