The more people mention this, the more I’m almost starting to continue trying it. If you really get used to it, it probably does make it easier to adjust the Y axis for headshots, while you’re turning through the X axis. Basically, if you have to cover more Y axis space on the mousepad to adjust the same amount of Y pixels on the screen, you’d theoretically be less likely to move too much in that axis, and overshoot where you want to place the crosshairs.
On the other hand, I’ve been using the same values for X and Y for decades. There’s a lot of accumulated muscle memory to reprogram.
Now I wonder how many pro FPS players play with different X and Y settings…