I'd encourage you to read an excellent primer on the subject: The Ascent of Money by Niall Ferguson. Money is a social construct, not anything tangible. You can create money from leaves you rake in your yard, and organize your neighborhood around how many leaves you have. You can all agree that the giant stone at the bottom of the bay belongs to the unfortunate sailor who lost it, and therefore he's still wealthy even though he can't get his giant stone back (true story). You can agree that the people who are oldest in society deserve the most access to credit, and give them services accordingly.
Basic point here is that wealth is derived from society creating connections and performing services for each other, not from holding currency. Currency is simply the oil in the machinery which helps facilitate these connections. It has no intrinsic value, and the easier it flows, the faster the engine can run. That's why the Fed conducts QE and money printing - it's about the economy, not the currency. Inflation is a side-effect but it's often preferable to loss of real assets and jobs and lives.
The need for currency oil is real! imagine if you had to sell a house, everytime you needed to get some liquidity.