When copying a compound polygon or line feature (SDO_GEOMETRY) with the Data Interoperability extension from one table to another, arcs in compound lines and polygons are converted into line segments.
The conversion of compound polygons or lines to simple polygons or line segments is the default behavior of the Data Interoperability product.
The addition of enhanced geometry model support allows lines and polygons containing arcs to be maintained, rather than stroked or the geometry being split up into multiple segments. It also provides the ability to truly hold measures.
For more information, see the 'Geometry Handling' topic under the 'Workbench Advanced Settings' section of the Data Interoperability Help.