Bitcoin is already a currency but it is not yet really used like the fiat currencies. The reason is that it is not yet supported everywhere as a payment method either online or offline. That is why people still considering Bitcoin mainly as an asset, they trade and hold it for making good profits.
the possibility could happen that no one can know for sure the crypto currency is going to grow in the future it will be like to be able to be a currency in my country but it can't seem because the government is still banning direct transactions with crypto currencies