Deadband in the input signal is not the same thing as hysteresis in the control loop. The servo will
always work hard if you have a varying load torque it is working against.
Hysteresis in the input signal is pointless for control, but it will stop a lightly loaded servo from
jittering if the servo pulse source itself is jittery - ie the Servo library has jitter due to the other
interrupts (timer0 interrupt that drives millis() for instance), having deadband in the servo will
reduce the chattering of that servo, but will also reduce the accuracy of that servo.
If you have a jitter-free servo controller such a dead-band isn't helping you, but it probably is
a reasonable compromise for the Servo library, and for analog RC control.