The initial idea of Bitcoin creator was for it to be a currency. It was created to be an alternative to fiat but due to the gain that the validity of the Bitcoin market brought, people decided to be holding it instead of using it as a currency.
Apart from the above reason, it is also known that bitcoin transaction fee is not stable and goes very high when there is congestion in the mempool. This is one of the reasons why Bitcoin refused to develop in becoming a currency instead of an investment asset
Nobody would be able to envision what would become of Bitcoin in a decade or more, so it's only plausible to continue to watch after the developments and the adoption of BTC both on the market and in the lives of some people and whole countries.
There are also solutions to high fees in dire times, just like Abiky said.