Well, if you haven't got a WiFi router, then yes, it will give you the ability to connect to the internet with your tablet. Xbox 360's does not have built-in WiFi, so you will either have to buy this little thing you put on the back to get WiFi, or use a cable. Also, if you have a WiFi router then the closer you get it, the better signal you will get. (sitting right beside it is obviously not needed to get good signal).
Using cable gives you better speed in general.
Hope this answered your question.