Create Follow-up Email functionality in Completed Campaigns

Summary: Can anyone explain what is the functionality of Create button in the Emails tab of a Completed Campaign.

Content (please ensure you mask any confidential information):
We are able to create a follow-up email on the completed campaign as system allows it and changes the status of Campaign to In-Progress. But the scheduled email is never sent and Campaign status is not updated to Completed. Please explain the purpose of this functionality.

Version (include the version you are using, if applicable):
26B

Code Snippet (add any code snippets that support your topic, if applicable):