If the Heavenly Venerable was one of the two saints of the West, then the path of the Ghost Immortal would have limited value before him, at most, it would be an Innate Magic Treasure.
But he is not; he is a saint of the Mystic Sect, a Taoist Ancestor of Immortal Dao. To him, the path of the Ghost Immortal is immensely valuable, almost comparable to an Innate Treasure.
Of course, strictly speaking, the value of the path of the Ghost Immortal still doesn't surpass that of the Immortal Slaying Swords. But what of it? The one speaking now is the Upper Qing Saint— he is threatening the Primordial Heavenly Sovereign.
If he doesn't hand over the Immortal Slaying Swords, then he will escalate the matter, bring it before Honjan Daizu. With this incident, the value of the path of the Ghost Immortal greatly increases, indeed reaching a level comparable to the Immortal Slaying Swords.
Agree or disagree?
The Primordial Heavenly Sovereign now appeared very hesitant.