Bandwidth explained
By bandwidth I am referring to the frequency range of the control surface commands. Because the Dutch Roll frequency is less than 0.5 Hz, there is no need for control surface motions at frequencies higher than about 1 Hz to provide increased Dutch Roll damping.
It is still unclear to me what examples grounded27 is pointing to when stating: "If you would watch a modern rudder (controlled by a computer actuated by the rudder actuator) you would see a flutter or rapid constant reaction to dampen yaw". Specifics on airplane type and phase of flight would shed more light on this topic.