A publishing company has been using Media Cloud for the last six months and now...

Comprehensive and Detailed Explanation From Exact Extract:

Named Credentials in Salesforce are used to securely store external service endpoints and authentication details such as client ID and client secret. When integrating with Google Ad Manager, the client and secret are used for OAuth authentication. Named Credentials simplify authentication handling for callouts by managing tokens automatically and securely. Connected Apps are typically for OAuth client registration but not storing credentials in this use case.