True, but ...
money is a social construct after allAnd each piece of it is worth what each person chooses to give up for it. You'll give me an hour of your time for one that has a picture of Ben Franklin on it? Cool. You'll take a Washington? Even better (for me). As long as no one is coerced into giving up more time or goods than they want for a particular amount of money -- or vice versa -- everything's good.
But what happens when I want to trade my labor for some of my neighbor's goods? He wants a new website, I want his used car. We agree to the deal, and everything's good. Until someone notices that I didn't pay any taxes on that car, and he didn't pay any on that design work.
If money is a social convention that we all choose to respect because we can't always find someone to do a one-to-one barter with, that's great. But when the government won't allow you to barter without assigning a monetary value to what you've done and paying taxes on it, that's coercive.