Great! I'll happily advertise for Ghost. As I said I'm not affiliated but I am a fan. I especially am a fan because I have a huge respect for open source organizations that run their business like they do.
This seems like a positive aspect for a blog? Most blogs are pretty far removed from being “applications”.
Why wouldn't you try to bring the best possible experience to your reader?
A blog is (usually) a collection of documents. For this use-case, using standard hypertext (standard HTML documents delivered over standard HTTP to every standards-compliant browser) does bring the best possible experience to your readers.
Delivering a single HTML document stuffed with some hand-crafted Javascript code trying to re-invent hypertext will not bring a better experience to your readers (especially not any readers who disable JavaScript), unless your blog is something more specific/unusual than a collection of documents and actually fits something other than hypertext better.
Static sites are fast and don't require untrusted code running in my browser.
And its quite possible to make a SPA that renders on the server and serves you an html but then maybe we can show just half the information so we don't send too much info to your browser.
2. When I first discovered Ghost (last year) and I heard it's using NodeJS I was expecting a beautiful, responsive, SPA blog engine that is fast. After reviewing it and even trying to use it as a platform for a newspaper I found that (It's just wordpress and it's not using the power of javascript to it's full extent.)
Fast => I could and I did built a faster wordpress site.
SPA => Nope
Customizable => Nope.
For me it's not worth the extra capabilities instead of a static blog.
I found gatsby(1) great for all my use cases and with some extra work[2] is more dynamic that ghost.
1. gatsby - https://github.com/gatsbyjs/gatsby
2. netlify + contentful - https://www.netlifycms.org/ + https://www.contentful.com/
(I would love to see a CMS that embraces SPA/PWA. On the other side I would hate to serve 1mb of JS just to show 4 paragraphs and 1 picture)