Use Multiple System Boundaries for Use Cases
Provides a use case view of the entire end-to-end process
Capture the multiple systems needed to support the complete user experience
Highlight roles that must use multiple systems to do their jobs ("swivel chair" user experience)
Bring attention to the interfaces (automated or manual) that must exist to exchange data between systems
Show the complexity of interconnecting systems at a high level - can be used as a communication tool with business stakeholders and implementers