What is deadband? In the real world, gimbals could detect attitude changes to within hundredths of a degree, so the RCS would be firing constantly to correct the ship's attitude every time a very small attitude error occurred. This wastes a lot of RCS fuel. So a dead band was introduced into autopilot systems. A deadband is a attitude tolerance region in which no automatic attitude correction happens. This deadband was customizable and was adjusted as needed. So for example instead of the RCS firing every time a 0.01 degree of attitude change occurred, a deadband could be introduced within 1 degree of attitude change, so the RCS only fires if the attitude error exceeds 1 degree. This saves RCS fuel as it fires less often. The dead band can be set to varying deviations as required depending on how accurately you want your spacecraft to point in the direction you want. How is it useful in Kerbal Space Program? As it is useful in real life to save RCS fuel, it would help save fuel in KSP too, especially in large spacecrafts like space stations. I've built 2 large space stations and noticed that they use a large amount of RCS fuel as the RCS keeps firing very frequently to correct the space stations attitude and this causes the space station to swing and more RCS is used to try and stop it from swinging which just keeps the swinging going. It would also reduce the annoying twitching engine nozzles do on a small spacecraft as they change direction every millisecond to counter attitude errors when using the SAS. So my suggestion is to add an option in the command module control panel to toggle and set a deadband to the degree you need.