A potential profit point would be providing the legacy compatibility, any necessary personnel, etc., for so cities and other slow movers can still use the old s

A potential profit point would be providing the legacy compatibility, any necessary personnel, etc., for so cities and other slow movers can still use the old system to set up automatic withdrawals, but implementing a client-side control over each of these hooks into your accounts. BankSimple could charge $5/mo to allow you to use the personnel that will configure this manually while people hooked into the API will be able to register hooks for free. This could be done now by any major bank, but it isn't done because banks want you to unexpectedly lose money in hopes that you will overdraft. There are many, many problems in banking like this; not much technical overhead to solve, but the banks don't want to solve it because it stands to affect their predatory profits.