A:Answer If your windows computer has bluetooth, you don't /need/ this adapter, however, I found with bluetooth that my controller would drop at times. I searched online and found others had the same problem. Someone said this adapter fixed that so I bought the adapter and it's been perfect ever since.
One nice thing about the adapter is that you can put it on a usb extension cable to get it closer to the controller - I have a cheap little usb hub on my desk with all my wireless adapters (mouse, keyboard, xbox controller) - this way the wireless signal doesn't have to pass through the top of my desk, nor any metal.