They wanted the mouse to have a name like “Microsoft® Wireless Notebook Presenter Mouse 8000” but they accidentally used the wrong encoding and the name was invalid. Because they already made thousands of devices without properly testing them, the “obvious” solution was to patch the Bluetooth stack on every single computer in the world to fix this issue. It’s the only Bluetooth device released in computer history that requires this.
The WMO was the pinnacle of gaming mouses at the time and it was just an ugly office mouse everyone had around.
I still have one because it was so coveted and they stopped producing/providing it.