The three Spiritual Treasures are the Hundred Ghosts Chart, Black Skulled Shield, and Purple Pupil Bead. The ghost creatures in the Hundred Ghosts Chart have all been slain, rendering the treasure of little use unless several Nascent Soul Stage ghost creatures are cultivated. Hence, it could be traded with ghost cultivators.
The Black Skulled Shield is a defensive Spiritual Treasure with comparatively strong defensive capabilities. The Purple Pupil Bead is an auxiliary Spiritual Treasure that allows the wielder to ignore restrictions and see farther, compensating for the limitations of the Hundred Eyes Cicada.
Shen Long killed Qin Biao and his two companions without obtaining a single Spiritual Treasure, but after slaying Zhao Xueying and her three companions, he acquired three Spiritual Treasures. This alone reflected the strength of the Heavenly Ghost Sect; major sects are indeed different.