Bitcoin is not an asset, Bitcoin is money and the definition of money is a currency (ie. a medium of exchange) that can be used as store of value. This means because Bitcoin is acting as a store of value and also because it is in its early stages of adoption, its value keeps growing against fiat making it a suitable investment.
Calling Bitcoin an asset is like ignoring everything else that it offers which are far more useful.
Well I quite disagree with you on this, bitcoin is an asset, there are so many characteristics of bitcoin that makes it to be classified as an asset, just like the one u made mention, store of value, this among the characteristics of bitcoin that makes it to be considered as an asset, this property of bitcoin to be able to store value for a long time is what makes it an asset or we can also to be financially asset or an intangible asset.