That’s right, Ghost is only being used as a content management interface, and is not responsible for the site frontend.
Netlify serves the content from its own servers - your build script will generate files, and Netlify will take those files and serve them just like you would static HTML.
Ghost has the ability to set the host for the admin panel - in the case of Ghost(Pro), you have your
.ghost.io domain as well as your dedicated domain (for example,
docs.ghost.org) which actually has the frontend
So, to answer your question, unless you use a more advanced server configuration, the admin panel for Ghost will be hosted on a domain different than where your content is hosted
This isn’t really something super necessary - it’s more of Ghost having a larger feature set, rather than something everyone should use. If you have a use case for deploying static sites in this method, go for it, but using Ghost as you have been for the past few years is still a completely normal and functional method for managing your site.