There has been many test done I can link you to that show an increase in performance when using a more stable polling rate, it's more than just numbers. The reason only test shows these isn't because it has no effect on you it's because it's so subtle that you don't know that you're performing worse, or at least you can't pinpoint it on your hz.
At the end of the day it is all preference, I love the responsiveness of 1000hz and if you do too then use it. But if you're making micro-adjustments or anything then it will negatively impact you but again that isn't detectable by your eye you don't notice your mouse having small missteps like that but it does affect your aim quality. Furthermore on the xim 500hz is less jittery as well, so it's all about how you prefer your gameplay
Do you want something super responsive, fast, and touchy? Or something stable, smoother, and more accurate, at the cost of the things above. Those are the two sets you can choose from and either or it is a slight sacrifice but on the XIM these effects are amplified due to it just being an emulation and not the real thing. Also my original post was informative not persuasive I'm not trying to change anyones mind, I'm trying to make sure no one buys a mouse just for its internal processor. It's a really dumb idea to do that, especially since it's useless on the XIM.