4000-8000 Hz Mice Are Not for Everybody
The general concept of a higher polling rate for mice being good is correct, but some people do not fully understand the consequences of running a higher polling rate on their system. If you do not meet certain criteria then the extra Hz your mouse is polling does nothing but slow down your system.
Here is what you need to keep in mind.
Your Hardware Matters the Most
There is no point in buying a 4000-8000 Hz mouse if you do not have a high refresh rate monitor and a beefy CPU. If you do not have the capability to run your monitor at 360+Hz you will barely feel any difference between a basic 1K Hz mouse and an 8K one.
More importantly, if you have a PC that is on the weaker side buying an 8K mouse will do more harm than good. Without a good CPU/RAM, the FPS you will get in most games will fall dramatically. This reduction in FPS will result in a much higher latency increase than the decrease you could potentially get from running 8000 Hz on a top-end mouse.
In short, if you do not have very good hardware that can go hand in hand with your 8K mouse, investing in one is a waste.
Optimize Your System
Besides having good hardware you need to have an optimized system. You need to run a lightweight OS install, possibly OC your CPU/RAM, in short for you to benefit from higher polling you need your system to be ready for it.
In some cases, people have beast PCs but have their systems trashed leading to stutters and bad FPS in games while using a high polling rate mouse.
TL;DR
4000-8000 Hz mice are not as simple as plug-and-play since they need specific hardware and system optimizations before making good use of the extra polling rate. If you do not have the necessary hardware or do not want to commit time and effort you might as well just stick to 1000 Hz.