Hmm currency.
Is bitcoin a store of valuy? I guess not? The only intrinsic value it has is the ability to move value around. If you do not exchange value into bitcoin i.e. USD/BTC it would be worthless.
it is a medium of exchange, which does not make a currency. Blockchain is a payment rail and bitcoin is medium of exchange.
Or explain to me what makes it a currency?
Then what is fiat to you? It does not have an intrinsic value too. It only has a value because people believe in the state being able to back this value. That's all. And people believing in other bitcoiners to back the value is true too. So no difference on that point.
If you are with your USD-Note somewhere in africa and no one around then your intrinsic value is not existing too. You can't eat or drink it. The only difference is that it might be harder to find someone who accepts Bitcoin than you will find someone to accept bitcoin. But the same is true to north korean money when you want to buy something with it in an african village.