I've never met anyone who does this. I've never HEARD of anyone who does this. I cannot think of any possible reason WHY anyone would want to do this.

So why is it an option in so many games?

Why do so many games not even offer the option to change the X and Y sensitivity together? For a LOT of games, you have to set both X and Y independently, and make sure that you set them to the same value.

When you can just type in a number, or you can click increase/decrease buttons to advance the numbers, that's fine. But there are some games where it's just sliders, and you have to oh-so-carefully drag each slider, until the readout (which often goes to three digits after the zero) is where you want it.

It's not a huge problem, but I'm just asking: is there even anybody out there, who really wants to have different sensitivities, on each axis?

I'm not judging. I'm just really, really curious.