Force Feedback is not only implemented into steering wheels but, when I remember correctly, first came up in joysticks (Mircosoft Sidewinder me thinks).
Today you find it in all kind of controlers:
- Joysticks
- Gamepads
- Steering Wheels

You can simluate many kinds of "forces" to the player.
E.g.
In a FPS when you get hit (by a shot or something else) you could feel the shock in the gamepad.
Or when you crash into a wall playing a driving game etc.

There are many possibilties and I would like to see force-feedback either supported by 3dgs or by a plugin too!