Activity vs. Sequence Diagram for ATM

Because activity diagrams highlight the operations and data flows (intuitive for non-engineers), while sequence diagrams highlight the objects and messages between them (preferred by engineers) — together they give complementary views of the same process

Explanation

Both diagram types are valuable because they emphasize different aspects. Activity diagrams are intuitive for non-engineers and show the data processing flow. Sequence diagrams are preferred by engineers and highlight object interactions and message passing. Developing both ensures all stakeholders — engineers and non-engineers alike — have a model they can understand and validate. They are complementary, not redundant.