Broke lives matter
Imagine you're an ancient king and you wanna invade your neighbor. Your army will need stuff. One thing you could do is enslave blacksmiths and farmers and so on. Slavery is a tough sell though. Slaves tend to resent being slaves, so you get running away behavior. Not to worry, there's a better way. You make coins and you give these coins to your soldiers. Then you tax everyone in your country in those coins, on pain of being eviscerated by your new soldiers. How does everyone get coins? Why, by selling boots and wheat to soldiers. Boom. Your soldiers are supplied. Not only that, but do you notice, you've created a system that people literally buy into. They WANT to supply your soldiers because that's how you get these coins that everybody wants. You know, we could just do that for everybody. We could give everybody money, not just soldiers. Then, boom, you've got the whole country providing for itself. You don't even need to give everybody THAT much. Imagine...