When is “after a long wait” a useful addition to “the traveler arrived”?

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

• When every sentence must contain at least five words
• When an adverbial is always obligatory after a bare verb
• When the first expression is exclusively nominal
• When the long wait is a relevant part of what must be conveyed