Which of the following options is correct regarding hidden columns in aggregates?

Hiding columns in an aggregate primarily influences the presentation layer of the application rather than altering the structure of the data itself. When columns are hidden, they are still processed and included in the underlying data retrieval by the aggregate, but they simply do not appear in the final output rendered to the user or in any binded UI element. This feature is particularly useful for maintaining data integrity and security while allowing developers to refactor output views without altering core aggregate logic.

The other statements do not accurately reflect the function of hidden columns. For instance, while empty columns in a database might not generate any output, they are not automatically hidden by the aggregate. Additionally, hidden columns do not contribute to optimizing performance; their primary role is related to the visibility in the UI. Lastly, while hidden columns are not visible in the output, they are still part of the aggregate's data processing, distinguishing them from being completely excluded from the aggregate itself.