For such things, there are at least two options that work - the first is payment processors that act as intermediaries between you and the seller - you send cryptocurrency, the intermediary pays the seller in fiat currency. Another option is a virtual cards that you can buy for cryptocurrencies - and with a Visa/Master card you can pay everywhere they are accepted.

Of course, it will be much easier for some people if (when) banks enter this game in such a way that there will be a BTC logo at the entrance of the bank, but such people have never and will never understand that they are doing the wrong thing. Bitcoin was created as an alternative to banks, not to become dependent on them.