Crypto currencies are wholly dependent on electricity.
Money historically has been used as an easily portable wealth storage device.It doesn't matter what physical form it takes, as long as everyone agree on the same unit.
Besides coming out of thin air with no physical wealth behind them, what good is a Bitcoin going to do you when you are out in Bumfuck Egypt and your 4 wheel drive breaks down and needs to be towed and the nearest cell phone tower is a hundred miles away? Joe Camel Jockey can hook up a few donkeys and drag your rig to where it needs to go. How are you going to pay him if all you have are Bitcoins?