Bitcoin is still difficult to call the currency. This means of payment. As cheques. They can pay for goods, but to call their currency is not possible.
It is currency (money).
I dont think you have an understanding of what currency is
If lets say 10 friends agree that chicken bones are currency to them and they agree to exchange it for services, then that is currency/money.
Bitcoin is money / currency because someone out there will give you something for it.
This is not to be confused with bartering