Backers can sponsor gods as well as crawlers, and a sponsored deity behaves very differently toward its patrons.
Sponsorship extends past crawlers to the gods themselves. Theia has ugly history with the Ascendency Pantheon and is a poor bet to win the throne, so nobody ever sponsors her — until this season, when someone in the employ of the The Pacifist Network bought her because she is Samantha's mother, hoping to save Carl at the end of The Fifth Floor. The sponsorship is what kept the enraged goddess from causing problems and got Slit killed on Carl's behalf.
Not every deity is purchasable. Khepri is obscure enough that he isn't even available to be sponsored, functioning essentially as an NPC. That asymmetry is decisive: a sponsored goddess would smite Princess Vinata for Carl, so the sultana must run to the unsponsored god instead.
The market mechanic that turned a goddess into Carl's asset and closed the Sultana's preferred exit.
Also appears in books you've already read — spoiler-safe to their endings: