I read it as being able to dev your site in whatever you want, then scrape it and publish it as a static and seo optimized site.
What you can do with this is design your app as an SPA and have this give a quicker loading experience to any route that is “logged out” so to speak.
The problem is in reality you are logged in and what NextJS can do is allow you to define the subset of the page that can be static.