Encoder send a momentary key press in each direction of rotation.
SVMapper translate a continuous key press from a ON/OFF switch in ON position in momentary key press (what the games are designed to handle, with few exceptions in some DCS controls).
See the Encoder (from SIM point of view) like a rotary device that instead send voltage or resistance variation (like a potentiometer) send momentary key press.
The encoder code can be translate in proportional movement (like a axis) be appropriated controller, example mouse scroll wheel, or Saitek Trim Wheel, that use encoder instead potentiometer.
