Bitcoin is a currency not an asset.For example gold is an asset. An asset cannot be traded with other assets.But currency can.
Well in my opinion its both you can use it as a asset and as well as you can use it as currency because if you want to invest in bitcoin so it can give you a very good profit because this invest is an asset for someone and when you want to do daily trade you can also get a profit and as well as bitcoin can be used for daily expanse in your daily life.