Indeed, Post-Heaven magical treasures possess a spiritual nature. After Jiang Xiaobai scolded the two of them, they slowed down the rate at which they devoured spirit stones.
Of course, this slow rate was in comparison to their previous voracious consumption. In reality, the effect isn't much different - they still managed to devour over 15 million top-grade spirit stones in no time at all.
While consuming these spirit stones would significantly enhance their powers, Jiang Xiaobai felt a heartache each time he looked at these two wastrels.
What made him more heartbroken was that he had no idea how many top-grade spirit stones would be needed for them to completely break free from the suppression of this world.
He figured it would be a very long process, so Jiang Xiaobai decided to keep searching for spirit stone mines.