If you think normally then BTC is a known as digital currency or online money.On the other hand you think BTC is solved your financial problem then when BTC is your main asset because without BTC you can't survive.
Simply bitcoin is both Asset and a digital currency.If you want to invest your money means,you can use it as Assets.If you have a bitcoin earned by trading means,you can use that as a digital currency.Since many online transcation Accept bitcoin,you can use bitcoin as an Currency too