Given that the ocean is saltwater and thus not potable, I'd expect the glass of water to have roughly the same value by the ocean and in the desert. What defin

Given that the ocean is saltwater and thus not potable, I'd expect the glass of water to have roughly the same value by the ocean and in the desert. What defines the glass of water's price is how easy it is to get potable water where you are - in both your contexts, that's largely defined by whether there is civilization nearby. Either way, the glass of water still has intrinsic value - it will help humans and animals stay alive when drunk. Fiat currency has almost no such practical value (toilet paper and textile applications are two I've seen elsewhere in this thread, which is true for paper money but not cryptocurrencies). That's the point of the phrase "intrinsic value." It's not an _objective_ value, where the price is strictly-defined or inherent to the object. It's intrinsic, meaning that all participants in the economic system have a use other than trade for the item in question.