Ethan's conclusion about the Heavenly Items being of inferior quality…was 100% correct.
Although it was a Treasure Hall of the Greenfire Sect, it was only one of many. Moreover, in this Treasure Hall, only the Heavenly Artifacts that are useless to the Greenfire Sect are stored.
With the permission of the Grand Elder, any Supreme Elder could use these Inferior Heavenly Artifacts for the wellness of the Sect and thus, Ranulf used one of them to exchange for a Heavenly Spirit Beast from the Lin Family in the most 'Righteous Way' possible.
A Heavenly Beast like the Celestial Spring Koi Fish is a rare and invaluable beast for the Greenfire Sect.
However, that doesn't mean the Greenfire Sect would give up a proper Heavenly Artifact for it.
Moreover, the Sect didn't know exactly what kind of limitations the Celestial Spring Koi Fish had regarding the revivals and how long it would take to tame it.
