A quote on the functionality from the YouTube blog post:
YouTube Remote creates a virtual connection between your phone and YouTube Leanback. To ‘pair’ your phone with your Leanback screen, simply sign into YouTube Remote on your Android phone, and to YouTube Leanback on your Google TV or computer with the same YouTube account. Just like that, you’ve connected your powerful multi-touch Android screen with the biggest screen in your home. Once connected, you can use the rich browse and discovery interface on YouTube Remote to find and queue up videos to watch, and send them all to Leanback with a single tap. With YouTube Remote you can play, pause, skip forward and back and even control the sound volume.
Granted that they are touting some new functionality that we don’t have otherwise, but do we need a separate remote to control YouTube? Let us know what you think.