Let me blow your mind right now: all currency is fake. That's what makes it currency instead of bartered goods.
This. Times a million
Every currency (Yes, Virginia, even gold-standard currencies) are completely fake and arbitrary. The difference between fake and arbitrary fiat currency and fake and arbitrary gold-standard currency is exactly one layer of abstraction, because the "value" of gold is in itself pretty arbitrary. It is somewhat rare, but it's "value" is completely generated by the human mind. Which is actually for the best--can you imagine how high the price of gold would be if it was actually useful for something besides making jewelry and helping Fox News scam old people out of their savings with terrible gold investment opportunities?
Humans assigned "value" to gold because it was rare-enough to avoid hyper-inflation, but common enough that you didn't have to worry about deflation. And that worked just fine for a few tens of thousands of years... until there were too many humans for the world supply of gold to adequately represent new wealth and value as they're created.
If a more numerous race of aliens had evolved on this planet they might have assigned value to blades of grass, pebbles, or certain kinds of trees in a similar matter based on their own needs.
Which is why the entire "gold standard" argument (that "our money is fake and worthless") is so stupid: Yes, it is fake and worthless. So is all other money, everywhere--the value comes from the perception. So it doesn't matter if its "backed by gold" or "backed by Jell-O Pudding pops" the fact is, the value is based totally on the perception of value of something. With fiat currency, it's the perception of the value of what you can buy, with "gold-standard" currency it's the perception of the value of the gold. But neither has any "real" value without that perception.