I personally believe bitcoin will never replace fiat in this regard, maybe it can serve as an alternative when volatility becomes more stabilised, but for the mean time this won't work efficiently.
Bitcoin is a store of Value, and for that singular reason, it would have been very easy for countries, business firms, bith individuals and corporate bodies to adopt Bitcoin as a means of daily transactions, after all, it will store and increase in value. But we all know the problem here, the volatility. You can't have a business transaction with someone today, and it's value when the transaction took place was $150k, and in the next minutes or hours, the value has dropped to $120-100k, who would take that.
It will just be cool it remains the way it is, serving as a store of value and a hedge over inflation. If you understand the value of Bitcoin and you are willing to take the risk, you buy Bitcoin and store in your non-custodial wallets and HODL as long as you wish. Even in so many developed countries, Bitcoin is not used as daily transaction means. The level Bitcoin is operating I'm Nigeria and the number of citizens that are involved is just okay. I think it's a personal decision to make.