For Fred, a 30-year-old strategy consultant, one of the first challenges of moving to New York from London was getting used to his new Chase banking app. “Wiring people cash is clunky and you have to pay fees,” he says. “It’s a bit of a nightmare.”Revolut and Monzo, the two leading UK digital banks, think they can help fix this. Since they burst on to the UK scene a decade ago, they have attracted millions of customers with user-friendly mobile apps and lower fees for things like overseas transa...