One possible advantage I see is it creates a 1:1 correspondence between a website and a file.
If what I care about is the website (and that's usually going to be the case), then there's a single familiar box containing all the messy details. I don't have to see all the files I want to ignore.
That might not be a benefit for you and not having used it, it is only a theoretical benefit in an unlikely future for me.
But just from the title of the post, I had a very clear piccture of the mechanism and it was not obvious why I would want to start with a different mechanism (barring ordinary issues with open source projects).
That the page HTML is indexable by search engines without having to render in the server. Such unzipping to a directory served by nginx. You may also use it for archiving purposes, or for having backups.
