You're right, because day-to-day fiat functions very well. People get paid in fiat and pay rent in fiat and everything else. Why would I suggest that someone exchange their relatively stable currency for a digital one whose volatility can be breathtaking and whose legal status is subject to the whims of government? And a currency that offers none of the protections that banks offer?
These are the questions I can't seem to answer myself.
Even after also, people love to convert their fiats into bitcoin just for the faith they have on bitcoin ecosystem. The mentioned problems like volatility, regulation law are will fade away in time. I too believe bitcoin will function well and will outperform fiats for sure.