This is my other thought. Bitcoin in the first doesn't have the plan to replace fiat. Fiat is fiat and it can be replaced by bitcoin because in other ways bitcoin is bitcoin as well which can not be replaced by fiat either both are unique, both do have advantages and disadvantages as well. But they obviously are comparable that makes their differences.
Yeah both bitcoin and fiat have their own different features which are useful to us. Bitcoin is beneficial in the sense that it help us earn money and make business online, earn profits, hold our money free from any authority, etc. Also fiat is beneficial since it is the money we use in all our transactions everyday and is being used by many since in the past. So bitcoin cannot replace fiat as well as fiat to bitcoin because they have their unique features which both benefit people.