I want to ask a question, if there is a Bitcoin ATM card, and you want to use it to pay bills such as an hotel booking, will the payment reflect instantly while the atm machine or Miners still has to process the transaction?
As far as I know there's no Bitcoin ATM card yet but if it will have soon then that will be probably good. However, I don't think Bitcoin need this kind or card since mostly transaction held online.
For me, i do not think bitcoin can replace fiat totally, because when their are larger transactions to be processed, it takes hours or even a day, except you have to pay Higher fees to process your transaction.
Just like you pal, I don't crypto especially Bitcoin could replace fiat due to the fact that most of stores and other transaction is not ready yet for this kind of monetary system, so basically we aren't not fully ready yet.
One thing, crypto varies on how we will use it whether as a currency or a store value just like gold. Actually, I even once used some of my coins to buy something, or spend it into something but I do consider it as a store value. For me it is a currency and a store value at the same time.