WFC is brilliant here. By leveraging their primary asset (customer relationships) they have jumped to the top of the line in a new ability to deliver services, and capture unregulated payment revenue. Think they need to work quickly to ensure retailers see an upside to expanded Amex transaction volume (see payment enabled CRM).
There is a school of thought that “pricing debit” for consumers will help banks increase credit transaction volume (ie credit cards are “free” and have points, debit cards will have monthly fee). Merchants must therefore act to build incentives around debit card usage, or a decoubled debit like product (see blog). Target Redcard is clear leader in the US.