Can someone please let me know.
Yes this is can be for a scenarios where the form is part of a collaboration job, and its data may be rolled up and deliverer by a separate delivery process.
The Delivery Status of "Not Required" specifies that the transaction is completed by delivery does not need to be performed and PII data can be purged once scheduled data purge time has been reached.
This page describes the paths/meanings of different delivery statuses: Transaction Delivery
It appears it means just what it describes. The transaction has been deemed delivery not required, It appears that is an option under a custom delivery process.
Hope that helps!