A very common modeling technique is to create an entity that will be used across many subjects areas / diagrams. For example, the entity "Calendar Dimension" could be used in many places in the data model.
Having the ability alias it to these areas is preferable rather than a copy / clone, which requires the data modeler to find each instance of the entity and manually make the same changes. This can introduce defects that may not show up until in the dev cycle. With aliasing, which other data modeling tools support, allows the entity to be changed once, and the change will ripple to other instances, similiar to how templates work.
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