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.
A man who has even a single Bitcoin I think he has a good asset for him. As the value of Bitcoin increasing it is better than gold or any other currency. At the same time it like currency you have. You can pay bills and purchase things by using bitcoin. In short bitcoin is most profitable and beneficial asset to a person.