what are the benefits of rooting it?
For some, it is the ability to customize things the way they want. For others, it is the ability to put cutting edge (and sometimes unstable) future revisions on the phone... to get features not yet available to the public at large... for others it is the challenge.
Unlike the iPhone, rooting the Droid isn't so much a need (since you can install anything you want already), as much as a want... it is a geek thing, it is a challenge.
There's some info in this thread that might interest you.