Even for BTC or alternative cryptocurrencies to be eligible as money, they need to satisfy all attributes of fiat. To replace fiat, you don't have to be different but rather better than it. Fiat has intrinsic value, no matter how much we argue. The intrinsic value comes from coercion, pay your taxes or go to jail. Fiat has extrinsic enforcement by governments issuing denominated currencies, to determine its value. A 5 dollar is always a 5 dollar.

BTC lacks intrinsic value, people might falsely argue, sending transactions is the intrinsic value of BTC. Sending transactions doesn't give an edge for BTC to compete against traditional currencies. Until BTC doesn't have intrinsic value, replacing fiat would be difficult. One scenario where bitcoin would work as currency is when the global population, consider it acceptable similar to cowrie shells accepted by the people of Uganda.

I am bullish on Ethereum having a higher chance to dethrone the fiat currencies.