لأن معناه مقتضى ظاهر الحال
For it means what the apparent condition calls for.
Ḥāl (situation) includes relevant contextual indications, whereas ẓāhir al-ḥāl (outward condition) is the status initially apparent to an observer. Normally these coincide, but a clue or communicative aim can make another form more fitting.
For example, no verbal question has been posed, yet surrounding cues have made a listener eager to hear a particular answer. Speaking as though a question were asked is unusual on the surface, but can be appropriate to the full rhetorical situation.