I know it gets spellcasting, but I'm noting that you could technically enter the class with a binding class, and Archivist is better than Cleric, anyway.
And an alternate build idea would be:
Cleric 1/Binder 1/Anima Mage 10/Crusader 1/Ruby Knight Vindicator 7
Sure, you would need shenanigans to get into Anima Mage, but you would gain Vestige Casting and Divine Impetus. Now, can anyone tell me how good a Turn attempts->Swift Actions and "cast any spell as an Instantaneous action" is as a combo?
Also, a question: can you Vestige Focus, Expel Vestige, Rapid Pactmaking, or Improved Binding if you have the Bind Vestige feat? Because none of those feats, afaik, ask for the soul binding class feature