The basis of the public demand for all currencies is simple. A court operation invents legal debts owed to it by the public. This includes taxation. Then, the court uses coercion to promote compliance (or to confiscate the debts that they invent).
Then, the courts specify a method of payment that the public can use to pay the invented debts. When the court names the currency that they will accept, then that creates public demand for that currency.
Next, governments tend to create a monopoly on extortion by criminalizing unauthorized extortion. Governments regulate extortion (regiment it & ritualize it & organize it).