it's not about fast and cheap transactions, it's about immutable, permissionless, peer to peer transactions. without these properties all we have here is a terribly inefficient shared database hyped up with buzz words like "blockchain" ( XRP )
Bitcoin could have all these fantastic properties that you mention, but if it is too expensive for the average person to utilize then all of these fantastic properties are pointless and meaningless to anyone who isn't a whale or millionaire.
Bitcoiners who dismiss or downplay the transactions fees are rich elitists living in their own bubble who have little to no idea how bad these fees are for the average person.
It is pointless to make bitcoin legal tender in a country like El Salvador when paying even a couple of dollars transaction fee is a small fortune for an average person living in El Salvador.
Almost no one in a country like El Salvador can actually afford to use bitcoin.
Even in the first world, paying ten to twenty dollars fee just to buy $100 of bitcoin is ridiculous. It makes it impossible for anyone to dollar cost average, which is the point of DCAing and putting in small amounts over a period of time.