Hi Bill,
creation of Configuration Scenario is not a mandatory step ton run an interface End to End. Also from search you can identify each and individual object Integration Directory. But sometimes it helps to give you a picture that which different objects of different types are responsible to run the interface. It helps when other developer want to check the interface developed by me. But again nothing like 'must'. If you are Integration Team is maintaining this process, better to update / include new objects within the Scenario.