For Legendary powerhouses especially, the potions that would make ordinary people break through in level and increase strength had little value. Prolonging their lives and avoiding being killed by others was their greatest concern.
The Godly Soul Potion had no healing effect on various injuries of the body, unlike some healing potions or healing magic spells, which could even regenerate an amputated limb. However, no matter how effective the healing potions and powerful healing magic spells were, they still required time to take effect. Besides, they would only work on living creatures, and not the dead. The Godly Soul Potion could trap one's soul in their body for a long time, even if the body had been greatly damaged or was already dead with an intact soul (to some extent). That would be equivalent to giving them time to heal.