By passing on valuable and relevant intelligence, Calabast showcased her value to him. Even if she blackmailed him into becoming his partner back at the Starlight Megalodon, a one-sided relationship never ended well.
If she exploited him without giving anything in return, Ves would only grow more resentful at her. This meant that she would have to continue to find more ways to coerce Ves while watching her back for any betrayals.
Instead of pursuing this short-sighted course of action, Calabast made a decision that reflected the best of her Hexer heritage.
She decided to take advantage of the situation to become an equal partner to Ves.
Though Ves didn't want to admit it, her approach was working.
To ride the transit shuttle, you needed to pay the fare.
Providing intelligence and working to protect Ves in the dark was Calabast's way of paying the fare. By keeping Ves content, she could continue to ride him all the way up to the top.
