I think for now fiat currency is still very dominant in any field, whatever we want to buy, it is definitely fiat currency which is always the main choice, because there are still many countries that do not want to accept purchases in bitcoin, and are not ready to be paid with bitcoins,
Maybe if living in El Salvador we will get salary in bitcoin because bitcoin adoption is legal there, my country has not legalized bitcoin so I have to convert some of my salary in bitcoin for long term investment.
There is no chance to make a profit by getting paid fiat. But you can make a huge amount of profit by Getting paid in Bitcoin if you have characteristics for holding payment long term. Think about my salary, I've gotten 8 payments during the last 2 months, and each payment was received at a below $32k price range of BTC. Till now I'm holding the full amount (nearly 0.0064BTC~200USD @31K price) and decided to sell when the price will go $50K again. So, it is clear if I will sell it @50K price range then I will be able to make 60% extra profit by holding it for 2 months.