In most cases, the mere highlighting of structures is not sufficient for understanding a system. Even with a detailed plan of an oil refinery, it is difficult to understand how oil is converted into gasoline. Only when the process (flow) of refining is explained does it become understandable. Identifying flows is a powerful tool for explaining something. This is also true for models of the IT system. The static view of classes alone is not enough to understand an IT system. For instance, what happens in the IT system when a passenger checks in? Which flows are being processed? Which objects are affected? These questions are answered by the interaction view.
Just as important is the fact that modeling the interaction view contributes much to the verification and completion of the static view. By having to deal with class diagrams from modeling queries to the level of individual attributes, it is ensured that the class diagram...