To enable the recording of the form of a directly modelled part by automatically creating dimensioned and constrained sketches which would otherwise be lost when modifying directly modelled parts.
Believed advantage:
Where direct modelling gives the advantage of enabling greater creativity when creating parts - it lacks the recording of design intent which would otherwise be carried through subsequent versions and revisions of parts.
By automatically generating (editable) sketches of the bodies gives - in my view - an advantage in not having to choose convenience over design intent or vice versa.