IMHO, I think crypto Banks is a good option, But to replace the entire traditional banking system in just three years? for me it's not possible to happen even in a decade, Because the traditional Banking system is too big and we are talking here globally, thats why it's not easy to replace it, in just a few years, What I believe is the traditional banks and crypto banks will be working together side by side to prepare the world about the new digital finance revolution.