It depends on your definition of "fake," obviously, but it's not fake by meaningful definitions. It's a very real social construct. It's as "real" or "fake" (take your pick) as the value of gold, the right to own property, definitions of words, the rule of law, race, or gender roles. Of course it has meaning, because everyone agrees it has meaning. We could go back to a barter system to be more "real," but that would make every transaction incredibly expensive, which is why we created artificial signifiers like "shiny metal stores value" in the first place.