Including the businessMessageId (BMID) in both the message header and the application header helps ensure smoother processing and better traceability.
 

• In the message header, it allows for quick extraction, logging, and routing without needing to decrypt the message.
   

• In the application header (within the message body), it supports data integrity and makes the message more accessible and readable for business users.
   

This dual placement helps teams troubleshoot faster, maintain consistency, and ensure the message flows are both technically sound and business-friendly.