There isn't a single or right concept of how you should use your coins. If Bitcoin fits the function of investment for your life, then use it as investment, but if it suits better as currency for daily transactions, use Bitcoin as currency. It's not the developers who know better, but each individual who decide how they should use Bitcoin taking into consideration their needs on the present time.
Satoshi Nakamoto created it, listened to community to make more development before Satoshi Nakamoto decided to leave the community and give Bitcoin to the community for further development. The departure makes Bitcoin truly decentralized, without a centralized person to impact its development and future.
Bitcoin has many use cases and the
article writes about 10 most common Bitcoin use cases. I am sure a single person will touch not all of 10 use cases listed in the article. We have freedom with our money, free ways to manage our personal finance and Bitcoin gives us many options to do with it and our finance.