That's true, however, most mice with an extremely high dpi have a problem with negative acceleration if they are moved too quick and suffer from skipping. Also the user doesn't benefit from extra dpi and a low Sensitivity. A mouse with 900 dpi and an in-game sensitivity of 1 is just as smooth and accurate as a 5600 dpi mouse, however the 5600 dpi mouse requires less physical movement to rotate to player 360 degrees. The myth that more dpi improves your accuracy is untrue, because you can only be accurate down to a pixel on your screen. A mouse can't give you sub-pixel accuracy. the only time that more dpi benefits the player is if they play with a high sensitivity. A high sensitivity in-game and a 900 dpi mouse equals pixel skipping and a loss of accuracy. This is where a high dpi mouse comes in handy. High dpi just doesn't benefit low sensitivity players, as you can't be any more accurate than a pixel. Tons of people still swear by the old Microsoft intellimouse 3.0, which has 450 dpi, and is just as accurate and buttery smooth at a LOW in-game sensitivity as a Razer Mamba.
My point is, is that low in-game sensitivity players shouldn't waste money thinking that a high dpi mouse will help them. I had to learn this the hard way