If external SAP HANA Views are generated for BW entities the external HANA Views are displayed as BW entities in the HANA Data Flow.
With that functionality, you are able to work directly with the BW entities.
The same is possible for calls on tables/views of ADSOs and InfoObjects. The Data Flow identifies them directly as BW entity.
To use that functionality you have to maintain the HANA Schema Mappings.