وَكَوْنُ تِلْكَ الْجُمْلَةِ اسْمِيَّةً لِلدَّوَامِ وَالثُّبُوتِ، وَكَوْنُهَا فِعْلِيَّةً لِلتَّجَدُّدِ وَالْحُدُوثِ
A nominal predicate-clause serves continuity or stability, while a verbal predicate-clause highlights occurrence and renewal.
A nominal clause is suitable for presenting a state or relationship as established; a verbal clause foregrounds the happening of an action in time. The contrast can be seen between «Zayd abūhu qāʾim» and «Zayd qāma».
These are rhetorical tendencies, not logical guarantees of timeless permanence or of continuous repetition in every context.