At the moment it is an asset. To be used as a currency it has to reduce it´s volatility as well as it´s transaction fee and it has to increase it´s transaction speed. Most important though is the classification as a currency from government institutions.
Well for me, bitcon is really a currency but a lot of people in this world is adopt that bitcoin is also a great investment, that's why right now bitcoin is uses as a asset and not a currency, and also for me bitcoin is really an asset because it can gives a lot of people to make profit.