Ye Rong did not engage in a head-on confrontation with Ghost Devouring Daoist, as it would be an extremely unwise move.
The Hundred Poisons Seven Treasures held by the Green-Robed Ancestor are naturally top-quality items of the Ninth Rank, capable of destroying everything with the power they can unleash. While the Deadly Centi-Poison Asura Banner and the Deadly Centi-Poison Cold Demon Scissors held by Ghost Devouring Daoist are not likely of the same rank, they are exceedingly exceptional, as evidenced by their previous performance.
The Jade-Green Flying Needles and the Glazed Treasure Umbrella wielded by the Yue Zu Dai Pao brothers are unlikely to have a low rank, and yet they were easily severed and damaged by the Deadly Centi-Poison Cold Demon Scissors. Repairing and reusing them would be very difficult, unlike a slightly damaged flying sword.
One death in this manner could almost completely reduce this pair of Mount Wutai brothers' strength by a whole notch.