Well, that's why Bitcoin has been called as "Digital Gold" because of how many sees Bitcoin as a store of value. Some might say that Bitcoin must be used based on what's been written in the whitepaper. Bitcoin must be used as a currency where we can use it to buy things. Well, we can still use it, but majority of Bitcoin holders are storing it and treating it like an asset because they believe that if they will hold those Bitcoins, they will make more money as it appreciates hence, holding it instead of spending it.
Nobody can write something that is perfect and no need of improvement. Satoshi Nakamoto did great job from Bitcoin White Paper, code for Bitcoin Protocol, to big decision of disappearance forever but if Bitcoin has no space to change and improve, it won't be a good project.
Fortunately, Bitcoin project is not like that, decentralized in developments to network operations so if the community can reach to a consensus for a technical upgrade, Bitcoin protocol will be updated successfully for better things technically and practically.
Bitcoin has been growing up a lot from developments to adoption including its use cases and if it has more use cases in future, I won't be surprised and in fact I consider it as a good growth for Bitcoin.