A payment system people actually want to use is not just the system to move funds. It also needs ways to move funds back and meet the onerous compliance burdens anything financial eventually has to deal with and a thousand other little things at the boundary between the perfect little world of the system and the messy, complicated world of a modern economy.

No, it's not a complete solution and has too much shady speculation and sketchy exchanges. Furthermore, it's not a stablecoin.

Most people are not suited for using crypto in a serious capacity. Crypto puts the entire onus of keeping the funds secure on the holder, and one misstep on their part can see their entire wallet siphoned away in a fraction of a second with no recourse, and likely no punishment on the thief.

Banks have fraud experts on staff, they have people that can monitor activity and stop such transactions. Both sides have accountability so that the thief can be tracked down. Your worst outcome is getting your card skimmed and not noticing it in time to report the fraud unless you deliberately send your bank info to someone else. But even then, your bank can probably still help you.