The vast majority of the time, you don't need a wire transfer. And if your debit/credit card doesn't work on the weekend, you need a new bank; That's not the fault of banking as a whole.
Sure. But, examples like buying a high end guitar off criagslist, or a car from a private party, aren't less of a use case because they aren't every day transactions.
Having access to your money outside of banking hours is just one of many use cases I can think of off the top of my head.