What semantic advantage does “al-qiṣāṣ” have over the generic “al-qatl”?

Musāwāt and Ījāz al-Qaṣr: Proportionate Wording and the Rhetoric of Qiṣāṣ

• It specifies regulated legal retribution rather than killing generally
• It legitimizes all personal revenge
• It treats every kind of killing as the same
• It converts the statement to an imperative