Approval rates are not going to be any different whether one applies directly at the branch, online or via phone.
The bankers, however, have other tools at their disposal that can leverage any pre-approved offers and the like (i.e. cross-selling incentives). That being said, they can reach out to lending/UW in the event that your application is not approved and may merit reconsideration. While the banker can be your ombudsman in this process, lending/UW make the final determination.
