What is the primary purpose of a Use Case Diagram?

The primary purpose of a Use Case Diagram is indeed to provide a view of the system as a black box. This type of diagram focuses on the external interactions between users (actors) and the system, illustrating what the system does without delving into how these operations are carried out internally. By representing use cases and their relationships to actors, the diagram effectively communicates the system’s functionalities and the goals of different users without exposing the details of the system's internal processes.

This high-level overview allows stakeholders to understand the system's capabilities and user interactions, making it a valuable tool for requirements gathering and analysis. Since it's designed to capture user requirements in a clear and straightforward manner, it helps ensure that those involved have a shared understanding of the system's intended operations.