Bitcoin lately is becoming more of an asset due to its increasing transaction fees. Just lately, I can see some transaction accelerators asking for payments in order to speed up your bitcoin transaction which is sad. We will be expecting some more developments soon after this segwit2x fork. Lightning Network is coming up next perhaps next year.
It is not just investment but also a currency, Lol. There are many categories for categorizing bitcoin. Ether are numerous functions that are being performed by bitcoin all alone. It totally depends on the sure how he wants to sue bitcoin, those who are investors and want to make money with it are holding it for long time and earning large profits and so on. Bitcoin is adjustable currency and everyone can sue it.