In my opinion, currently bitcoin can be said as a currency and also an asset. When I invest in bitcoin, this means I have an asset in the form of bitcoin. And when I sell my bitcoin to buy something, this means my bitcoin as a currency. 
Correct. bitcoin is both asset and a currency (preferably a digital currency ) as it is populary known to work on most online transactions but investing isnt the only way to tell that bitcoin is an asset because there were also many ways in order to use bitcoin as a form of asset. few examples is trading , gambling , in other business ideas , etc... while on the other hand it is indeed considred a currency when we use it for buying something and as well as when we convert or sell it for cash and any other local currencies.