How does damaging ḥashw differ from non-damaging ḥashw?

Ījāz, Iṭnāb and Musāwāt: Standards of Expression and Their Distinctions

• Damaging padding preserves meaning; harmless padding spoils it
• Both necessarily convey equal benefit
• Both are exemplary forms of purposeful expansion
• The first distorts meaning; the second is idle without distortion