[CONNECT Update 16 C++] EC Classes: What has area?

The EC classes mentioned here refer to those found in two EC schemas delivered with MicroStation...

  • Base Element Schema (BaseElementSchema.01.00.ecschema.xml)
  • DGN Element Schema (DgnElementSchema.01.00.ecschema.xml)

A DGN Line Element has a corresponding EC class LineElement.  A LineElement has property Segments, which owns an array of one or more Segment. Segments has property TotalLength, which makes sense.  It also has property Area, which makes less sense since there's no obligation on Segments to make a closed loop.

A DGN Shape Element has a corresponding EC class ShapeElement, which inherits from MstnClosedBoundaryMstnClosedBoundary has property EnclosedAreaEnclosedArea applies only to closed elements, so is semantically valid.

But why does Segments have an Area property?  If the segments don't form a closed loop then what is the meaning of Area?  When is it appropriate to use the Area property of Segments?