On this screen, you can configure the key mappings for your external controller. This feature is particularly useful when games fail to recognize controller input but successfully detect keyboard and mouse inputs.
Pushing a button on your controller will create an entry for the button. Which after you can edit to your liking, such as mapping the button to a keyboard key, or a mouse key.
In example, if you want to bind mouse camera movement to the right analog stick:
This can also be used to control the mouse cursor within a container.
You can practically turn your controller into a mouse.