Maybe a little bit of a tangent, but another use for dead band is with multiple servos on one control. Some large airplanes use more than one servo to control a surface, some monster truckers use 2 servos for steering, maybe a throttle & brake servo on a large gas RC, etc. A larger dead band setting can help avoid having the servos fight each other, provide a little more tolerance for linkages that aren't exactly matched up, or may not stay matched.