The biggest banks in America move the money behind almost everything you buy. They haven’t figured out how to get you to click a button to pay at checkout. The digital wallets that allow online shoppers to click to avoid manually typing in their credit card numbers are largely operated by technology giants like Apple Pay and Google Pay and PayPal. On a small but growing number of sites, you might also find some banks’ entry into the field, called Paze. You might scroll right past it.  “Nobody knows Paze,” says Serge Elkiner, who runs it. “Like, what is Paze?”…