That’s not relevant to the point you’re responding to - the point is, if the purchasing power of your dollars went up (and assuming it’s your native currency),

That’s not relevant to the point you’re responding to - the point is, if the purchasing power of your dollars went up (and assuming it’s your native currency), you don’t get taxed on it because the number of dollars you hold did not change as a result. If you are holding a different currency, it’s value goes up, and you convert it back to spend, you made capital gains and it will be taxed even though that foreign currency is not an “investment” instrument.