Ijaz is useful when short wording makes meaning easier rather than harder to recover.
Ease of memorization: a compact expression is easier to retain.
Clarity of comprehension: irrelevant detail no longer distracts from the main point.
A constricted occasion: the time or situation does not allow extended speech.
Discretion: an intended listener understands an implied message without its being exposed to everyone.
Avoidance of listener fatigue: unnecessary length is suppressed.
In every case, the essential meaning must still be accessible to the intended audience.