A joystick is an input device that can be used for controlling the movement of the cursor or a pointer in a computer device. The pointer/cursor movement is controlled by maneuvering a lever on the joystick. The input device is mostly used for gaming applications and, sometimes, in graphics applications. A joystick also can be helpful as an input device for people with movement disabilities.
Techopedia explains Joystick
The joystick is mostly used when there is a need to perform a direct pointing or when a precise function is needed. There are different types of joysticks such as displacement joysticks, hand-operated joysticks, finger-operated joysticks, thumb/fingertip-operated joysticks, hand-operated isometric joysticks, etc.
Similar to the mouse in movement and usage, joysticks also include buttons, sometimes known as triggers. The difference between the mouse and the joystick is largely based on the fact that the cursor/pointer continues the movement in the direction of the joystick unless it is kept upright, whereas the mouse prevents the cursor from further movement until it is moved.
One of the noticeable advantages of the joystick is its ability to provide fast interactions, which are much needed in gaming applications. The joystick provides a much-needed gaming experience, which is better in quality compared to that provided by other input devices. It has a simple design and is easy to learn and use. It is often inexpensive.
The joystick, however, is not as easy to handle when selecting options from a screen and is not a preferred input device in such cases. Some joysticks limit the direction of movement to forward, left, right and backward, and do not offer diagonal or lateral movements. Again, the joystick is not as robust as other input devices, and, sometimes, users find it difficult to control compared to other input devices such as the mouse.