Big traditional banks have often been criticized for being late to the party when it comes to integrating customer-friendly technology. Early Warnings Services, the entity behind money-transfer service Zelle and backed by a group of large financial institutions, is launching a digital wallet later this year that will allow debit and credit card holders to check out at online merchants without entering their card details. For a while now, PayPal Holdings (NASDAQ: PYPL) has been the undisputed leader in digital payments.