A nominal description can be temporally qualified by «كان». It normally locates the predication in the past, without itself necessarily proving that the state ceased afterward.
«كان زيد منطلقا»
Zayd was setting off.
«زيد منطلق»
Zayd is setting off.
The core quality is similar, but the first expression adds a clear past temporal frame. The second relies on its unqualified or contextual time reference.
A temporal auxiliary becomes useful when the time frame matters to the listener. Its presence or absence should therefore be read as a meaningful choice, not a merely mechanical variant.