> USD has no value other than what it can purchase in the US.
Any currency has value for anyone—or, more importantly, any group of anyones—who gives it value. If a person in Botswana and a person in Namibia want to trade, and they're happy working in USD between each other, then it has value there.
any example token can have value, but will every example? no.
does the paper money of the US confederate rebel states have value? "any failed historical state's currency could have value to the people of Botswana" is not a useful idea.
Yes, I know, POWs used packages of cigarettes for currency, even those that had been passed around so many times that they were mush inside. I took econ too.
Any currency has value for anyone—or, more importantly, any group of anyones—who gives it value. If a person in Botswana and a person in Namibia want to trade, and they're happy working in USD between each other, then it has value there.