If your debts and bills are denominated in the currency of your country, the bills and coins have value because you know how many of them you need to pay what y

If your debts and bills are denominated in the currency of your country, the bills and coins have value because you know how many of them you need to pay what you owe. So yes, if we ever got to the stage where your rent is priced in some coin, that coin would correspond to a currency. But until then, it's more like a volatile stock and "currency" is a misnomer.