Surely the data store is the least interesting part of a blog. Or, rather, what competitive advantage does Elastic give to a blog that warrants having "Elastic" in the product name?
It reminds me of https://nodebb.org, the "forum built with Node.js" (though they've rebranded away from that) which always struck me as the opposite place to focus when selling software.
For example, none of my problems with Wordpress are related to its choice of database. Just like porting Wordpress to Elastic Search don't fix any of my issues with Wordpress. A blog is almost entirely defined by its UX.
On a better note, the platform seems pretty polished.