The resolution a mouse offers is far above any joystick. The mouse rolls 360 degrees in one full circle of the ball (if it's got one and not an optical mouse), and can roll several times before reaching the end of a mouse pad, giving potentially several thousand degrees of movement in one quick motion.
A joystick can usually only move a max of 180 degrees from one side to the other. If the joystick is set to control the view of the player, if you want to look around behind you, you move the stick to one side (so 90 degrees from center), and the speed that you rotate is determined by the rate the game has setup. Never blindingly fast. With a mouse, to rotate 180, once you have some familiarity with the speeds, you can rotate very precicely 180 degrees with one flick of the wrist.
If you were to have a race between a joystick and a mouse to perform 30 360 degree revolutions, the mouse player would be done long before the joystick player due to the fact that the mouse player can move his hand much faster than the turn rate in a game for a joystick would allow.