Well it did. One of the (probably lifesaving) actions that Sullenberger did was to deploy the RAT which meant electrical power was maintained. This was not a checklist item, merely something he though useful. This meant the computers were still firmly in control when the aircraft ditched and the stall protection they gave certainly helped the ditching.

Interestingly after the accident the NTSB and Airbus made a number of ditching simulations and it showed just how hard it was for pilots to achieve the correct entry mandated by the ditching certification (minimum speed, -1 degree approach). However one pilot, an Airbus test pilot, managed to do much better than this by levelling out at high speed and very low using the radar altimeter. He the allowed the speed to decay until the aircraft touched the 'water'. This unusual proceedure probably couldn't be done by many pilots but it could be done by a computer.