an example is a country has fully adopted crypto and they released their own stablecoin. they also legalize some other big crypto coins like bitcoin, ethereum, and some stablecoins like USDT or DAI. and you become one of the citizens of that country. which one will you use for daily transactions. stablecoins issued by your country's central bank, or mainstream crypto coins like bitcoin. or privately released stablecoins such as tether. or keep using cash because you are used to it. and give the reason why you chose that coin.
If they released an official stablecoin and it is much more convenient to use than mainstream crypto like Bitcoin, it's pretty obvious that people would use the stablecoin. Especially when we are talking about fees and transaction speed. Stablecoin can have those advantage.