When useing a mouse, muscle memory takes over. This is why when you alter sensitivity, it screws you up so much, until you adjust. When you want to turn x degrees to the right, y degrees up, you move from location A to location B. This is different from a gamepad, where fast turns are primarily based on time spent pressing in a direction. There is, however, always room for error. Overshoot, undershoot your destination on a mouse pad, and you have to make slight adjustments on the fly. Now the time required to move your mouse from one side of the pad to the other is very similar to the time it takes to move it an inch. The time it takes to make these on the fly adjustments dwarfs the actual movement of your hand. On lower sensitivity, missing your mousepad location by a centimeter leaves you still accurate. On higher sensitivity, missing by a centimeter is a miss. So lower sensitivity makes for more accurate shots. Higher sensitivity is more likely to miss, but manages that tiny edge in speed, not to mention the space of the Mousepad. Its a balancing act. But generally, lower sensitivity gives you the accuracy you want.
On a controller however, distance traveled on a mouse pad and muscle memory is not the issue. Press the controller, and you turn at a set pace. The amount you turn is a function of time, not distance. Higher sensitivity challenges you ability to judge how long you should press the button on the fly, but in return it allows for much faster aiming. And in a twitch game, that time is incredibly important. Time is really the resource that you are managing, not muscle memory. And so on a controller, you want to utilize that time as effectively as possible.
Nothing wrong with either style. Both are different, and even though a Mouse is more precise and faster, that doesn't make it more fun. I mean, its a lot more fun for me. I prefer it by leaps and bounds. But that's just taste.
