In line with your thoughts if bitcoin will become a legal tender or a real currency replacing fiat currency then there is no fun in bitcoin anymore since we can no longer expect its price to increase or skyrocket since its price will be stable. For me one of the asset of bitcoin is its capacity to increase in value that gives me more leverage and more income.
Which fiat do you mean?
US dollar?
Euro?
Pound?
Yuan?
Franc?
Bitcoin still is struggling to process more than 5 transactions per second, the whole bitcoin code wasn't designed to make bitcoin available for masses but rather used for those trying to avoid centralized and heavily controlled money ( the system not just the currency) bitcoin is indeed a perfect alternative to traditional banking industry but still a monetary branch, only a decentralized one.
People should start treat and see bitcoin as it is and not something that it can't or won't be. when you have a glass of water you can't have more water in it than it already contains.