Bitcoin created to be currency but bitcoin now is also good asset due to the increasing price of it. There is no problem whether bitcoin is considered as currency or asset, Bitcoin is a medium of exchange that better than the current currency that we use for daily life.
Does it matter if bitcoin was a assets or a currency? No it does not. In theory , bitcoin is currency but these days practically people are using it as an asset, a very valuable asset.
The thing which is far more important is how much one holds the bitcoins, the more you have the amount of bitcoins, the more happy you are seeing the price rise of bitcoins.
Bitcoin is the cryptocurrency, so you can call it is currency like Dollar. But better yet, I think we should use Bitcoin as an asset than a currency. The current value of Bitcoin is useless if you use it to pay small order. Therefore, save it and research new way to earn more Bitcoin, you will get rich.