The purpose of this device is to be able to use an X360 Wifi Controller on your PC, without it, you'll need a wired one.
You could by the Controller for Windows (cheaper?) or use an official 1st or 3rd party one for the 360.
I picked this up, it works great (for MAME and old school stuff... I'm not a PC gamer), but it really sucks when you have a PC and a 360 in the same room / vicinity. You have to (un) initialize and press the "find" button to tell each system to look for the controller in question...
I don't have any issues with my Logitech mouse, although they sit quite a bit away from each other (this base and my mouse's base).