They don’t call it funny money for nothing. The only guarantee you have of fiat money’s value is the promise from the government not to print up too much of it. That’s a sucker bet. From Thorsten Polleit at mises.org:
Now and then, it pays to take a step back to get a broader perspective on things, to look beyond the daily financial news, to see through the short-term ups and downs in the market to find out what is really at the heart of the matter. If we do that, we will not miss the fact that we are living in the age of fiat currencies, a world in which basically everything bears their fingerprints: the economic and financial system, politics—even people’s cultural norms, values, and morals will not escape the broader consequences of fiat currencies.
You may not notice it in your daily use of fiat currencies—that is, for instance, when receiving wages, buying goods and services, paying down mortgages, depositing money with the bank for saving purposes—that something is terribly wrong with fiat currencies, be it in the form of the US dollar, the euro, the Chinese renminbi, the Japanese yen, the British pound, or the Swiss franc. However, the truth is that all these fiat currencies suffer from severe economic and ethical flaws, which are actually not difficult to understand.
Fiat currencies are produced by central banks and commercial banks’ credit expansion. In fact, central banks in cahoots with commercial banks increase the outstanding money supply by extending loans to firms, private households, and government entities. It amounts to money creation from thin air or—in a way—counterfeiting money. Issuing new fiat currencies sets into motion a boom, an illusion of prosperity. Consumption and investment expand, the economy enjoys higher corporate profits, increased employment, rising stock, housing prices, etc.