Next.js Incremental Static Regeneration

How about "next export"

In these examples, we use next start to start our app. That means, we use a Node.js server to serve our static pages.

Usually, for static apps, we can use "next export" which generates a set of HTML files, and we can deploy them without running a server. (eg:- Using GitHub pages)

Q: Why did not we use "next export" in these examples?