For me, I think that Bitcoin is both a currency and an asset depends on how you want to utilize it.
You can use it as a currency when you shop online, or buy stuff, accommodations or services and use Bitcoin as your mode of payment. On the other hand, it is also being used as an asset, a valuable one when it comes to trading and investments. Personally, I am utilizing it more as an asset rather than as a currency since from where I come from, it is very rare to find a business that accepts Bitcoin as mode of payment, at least for now.