I don't see how ES could be an issue for a blog, it's not like Lucene indexes blow up randomly and keeping backups should be standard practice at scale even if

I don't see how ES could be an issue for a blog, it's not like Lucene indexes blow up randomly and keeping backups should be standard practice at scale even if you used a proper DB. Meanwhile, if you want a small deployment that also does full text search with a bunch of "smarter" features and some analytics, it would make sense to only use a single data store. All these in theory, as I haven't checked out the actual project.