Xbox LIVE Games is a great companion app to keep up with the Xbox ecosystem while you're away from your game console.
If you live inside the Xbox LIVE universe, this is a great app. It will let you customize your avatar, post status updates, and browse the Xbox LIVE catalog of games. While you can't download and play Xbox LIVE games, you can download and play games for Windows 8.
Xbox LIVE Games is more of a manager for your Xbox LIVE social network than it is for downloading and playing games. Although Xbox LIVE Games won't let you play Xbox LIVE games, you are able to link your Windows 8 device with your Xbox console to send over game pages you see within the Xbox LIVE Games app.
Xbox LIVE Games is a great app for managing your Xbox social network and seeing what games are popular on LIVE.