@Michael_Soprano this from AI Assistant:
Data Storage: The Default Campaign database serves as a central repository for storing audience compositions, segment definitions, and other campaign-related data. It provides a unified environment for managing and accessing campaign data without the need to import all of the data from the enterprise data warehouse into Adobe Experience Platform.
I think we are missing some documentation on that specific option from a FAC perspective.
Found a similar page this time for the Campaign UI https://experienceleague.adobe.com/en/docs/campaign/automation/workflows/wf-activities/targeting-act...