Your argument is like saying an American manufacturer whose British sales office accepts GBP as payments which are immediately converted to USD means that "GBP's use as a currency is moot in this case".
I can express the value of say a laptop for weeks, if not months, in USD / GBP, can the same be done natively in bitcoin?
Can you point me to any manufacturer or business entity that values something in bitcoin instead of mapping it to a fiat?