Chapter 724: Devouring Alchemy Recipes 2

One should understand that pills and alchemists weren't separated into Grades because the Pill Makers (their official title) of the Martial Spirit World were bored. It was done because pills of a certain Grade were most effective on cultivators in that exact Cultivation Realm. Those with a higher Cultivation Realm would only benefit from diminished effects, while they were actively harmful to those of a lower Cultivation Realm. 

The Qi Purifying pill was a Grade 10 pill because of the materials used and its potency. As its effect stated, it would condense the Qi within a cultivator further, which had the effect of making their flow purer and could even create more space for them to increase Qi reserves. 

However, this was meant for Integration Realm experts, who were already the peak of the world. It was a pill with little use to them, which was why the association had made Draco make it.