It is either both because it'll depend upon the usage of the cryptocurrency. Some use bitcoin to pay for services and goods, while others prefer to keep and view it as asset.
My dear, in fact, it is not just like you like, it would be too easy ! It depends of the country you are from. In Japan it is considered a currency, but in most of the countries it is an asset and thus it is not taxed as long as you do not turn it into actual fiat money.