Firstly, there's the potential of tapping into all that traffic within its "walled garden". It's like a whole universe in itself.
The other thing is that it's very easy to build content on Facebook pages. You just need to share some interesting links with some thoughtful text around them. As you find and add this content you're putting more ideas into your own head. And if you let these marinate for a while, you can come up with some great ideas for longer posts that you can add to a blog.
Speaking of blogging: Getting comments on your posts is desirable, of course. Similarly, getting people to comment on your Facebook page updates is really important. That's why it's a good idea to ask for input, just as you would on a blog. And to reply soon, too. Not only will the fans who comment be more likely to do so again, but other people will see the interactions occurring and be more likely to add their thoughts.
Also, quite a few blogs have Facebook comments installed. So if you log in as your page and comment on those blogs they will appear as page updates. Along with your comment, Facebook grabs a bit of the blog post, as well as an image if there is one. So you're building interesting content in two locations at the same time.
You should seek out other Facebook pages in your niche and participate in them as well. This is like promoting a blog with comments. If you keep at it, making relevant and thoughtful contributions, more and more fans of these pages will get to know you and have a look at your page. Some of them are sure to become its fans.
What do you think? Is it valid to see a Facebook page as being much like a blog? Or do you think the analogy is not accurate, and a different approach is needed?