Your Psyker powers, at first a path seeming to lead to dangerous corruption, have now become holy and pure.
You gain access to the miracles & "holy" powers of the Adeptus Sororitas & the Ecclesiarchy, you can more easily purify corruption such as that of Chaos, and your "regular" psyker powers are rendered completely safe, removing problems such as Perils of The Warp or letting Chaos into a dimension it didn't previously have access to.