Earlier quoted context omitted.
As many others indicated, static sites are much better unless you need dynamic features. Static sites make deployments much easier, doesn't depend on any OS/runtime, doesn't lock you in to a particular database. You just write markdown and with little to no modification, the same thing could just work on Hugo, or Jekyll.
I use Jekyll; I used Hugo and Pelican in the past. They solve a very specific use case. But if you want to allow guest posting on your blog, a static site will not do. You need something that has drafts, that has a proper editor, that has a UI you can add and invite people to. Ghost solves that.
They do have some support for local caching, but investigating that is on my todo list.
One big upside of this design is seo: your blog isn't on blog.domain.com, but wherever you want it on your main site.