More so those who might be swayed by a quotation of Truth to Power, as someone unfamiliar with the book might and have go ‘Oh, that’s actually really interesting, I guess you’re right.’ The book is a citation nightmare because much like Unveiling, it’s meant to deceive us. Except at least in Unveiling’s case it’s propaganda meant to sway us to the Witness’s side and gives us a glimpse into how they see themselves and the Traveler, Truth to Power is just layers and layers of misinformation and deceit propped up by truths not directly tied to Savathûn’s motivation.

Orin was Awoken, I don't know what Xur was but he and Orin serve The Nine.