Some things are valuable because they're useful, or because people want them. Others are valuable because the government says they are.
For hundreds of years, money has fallen into the second camp. It has little intrinsic value in itself, but governments have backed it up...
People are so brainwashed into thinking that non-backed government fiat currency system existed "for hundreds of years". They seem to miss completely that it is in fact an "innovation" brought upon us a few decades ago and predictably falling apart right before our eyes. Oh well...