When to use Publish Required in Document of Records setup?

Oracle has explained this clearly in one of the 2018 release updates with an example.

Publish Required: You can make a document record visible on the UI from a specific date. The Publish Date field is now configured to be entered using HDL only, and not from the UI. If you want the document to be visible only after a specific date, you must select Yes or No in the Publish Required field on the Create Document Type page. For example, if you want to make the promotion letter visible starting 1-Apr-2018, select Yes on the Create Document Type page. Then, pass the date of 1-Apr-2018 in the Publish Date field using HDL, when creating document records for the worker.