The upside is that it's easily shareable, the login could be given to anyone who wanted to edit it - and also it's quite nice that it's done under the umbrella of a social media site.
The downside is that it's hosted by FB, and subject to their whims of mucking around with the layout.
I guess it's whether anyone has the time or inclination to convert a timeline into status updates, panels into photos etc. It's a bit of a monstrous task.