If i gave an American some swiss francs or Japanese yen it would be awkward to use it in 'the loop' you describe, but not impossible - they are still currencies.
They would work just fine if I travel to Japan or Switzerland. The loop doesn't have to exist everywhere, but we need a loop somewhere.
[/quote]
But there is a btc loop, my point was that it was just hard to go through it for btc users, but it does exist (comparing the convenience of someone in usa tryng to use foreign currencies. They need to go to a lot of effort to use it, like btc users do, but doesnt change status of foreign currency as a currency).