So, in what cases would noindex actually be used?

[robiulhasan]

Roughly speaking, there are two cases.

If you're editing a page and don't want it to appear in search results
If removing a page would disrupt the site's usability
When you are editing a page and do not want it to appear in search results, it is because you are in the process of editing the page or testing it and do not want it to appear in search results .

In addition, cases where deleting a page would impair the usability of the site include sales marketing directors, managers email lists 404 error (not found) pages, document download pages, and duplicate content.
A 404 error (not found) is a page that is displayed when the page does not exist at the accessed URL. It is not necessary to display it in search results, but if the error page disappears, it will not be possible to inform users that the page does not exist at that URL, which may impair usability.
Similarly, for download pages and duplicate content, if you cannot delete them because they are useful to users, but you do not want them to appear in search results , it is recommended to set noindex.

(Related article: "6 Must-See Report Creation Tools for Google Analytics Users" )

SEO effect of noindex
Noindex is one of the most important SEO strategies.