Money gets its value from its ability to make settle transactions. The most important of these are the settlement of obligations and liabilities, the transactions we have to make whether we want to or not. If we can only buy valuable goods or high-returning investments in a specific currency, then that gives the currency additional value. Historically, currencies became reserve currencies because their country of issue became the leading provider of the high growth sector. If you overlay the history of currency reserves against the data in [[Racing to the Top]], or [[Leading Sectors and World Powers]], there is an interesting overlap. The failure of currencies to gain adoption (Libra) might be because there is no need or incentive to use them. The need to settle liabilities is the strongest incentive for using a currency (and not necessarily the only one).