People get way too hung up on the concept of "hard" currency. It really takes some study of economic and financial history to understand that currency is just a means to an end, and that hoping for some immutable piece of value in your personal vault isn't what powers our world. Money is far more abstract than anything in the crypto world, and that's why it's not a good long-term bet.

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.

>> currency is simply the oil in the machinery Oil is pretty darn valuable.

The need for currency oil is real! imagine if you had to sell a house, everytime you needed to get some liquidity.

You're describing credit, not currency. You can access credit to fund daily transactions without touching the principle of your investments. That's what a credit card does.