Hmm, whether it's Human Refining or Demon Cultivation, as long as it's an inner core, it can be consumed to nourish Qi.
After all, it is a collection of the essence of heaven and earth, and the brilliance of the sun and the moon; once refined, it's fine, just like Elixir Pills.
However, the 'Golden' Pill from the Demon Palace is not viable. It and inner cores don't work on the same principle, plus the metal's special texture doesn't seem to belong to the Taiji Realm, rendering it unabsorbable by the human body, nor can it be refined into Divine Gang Qi. It's naturally unusable as Gold Essence Iron Seed, quite rare, indeed unique.
