جَاءَ الْعَامِلُ وَهُوَ يَحْمِلُ أَدَوَاتِهِ.
The worker arrived while carrying his tools.
Wa-huwa yaḥmilu adawātihi is a nominal sentence: huwa is the subject and the imperfect verbal clause is its predicate. The entire clause describes the circumstance of arrival, while the pronoun links that circumstance to the worker.
In jāʾa al-ʿāmilu wa-ḥamala adawātahu, wāw more naturally coordinates two acts. The diagnostic is not the presence of wāw alone, but the grammar and the relation intended between the predications.