Zatanna was basically being used a plot device, so they could finally be done away with the baby thing, since it made Selina look bad, and as a rival to Selina, so Selina could act all indignant and kick her ass.
It's kinda funny, the Batman books had been developing Bruce and Selina since Brubaker's run on Catwoman and Loeb's run on Batman, but Geoff Johns hates Catwoman for some reason. So he saw to derail her character in JLA with that "Crisis of Conscious" arc, where it's revealed that when the JLA mind-wiped all the villains that learned their identities in that forgotten silver age story that was used in Identity Crisis, Zatanna went a step further and also changed Catwoman's personality, who was among the villains, to be less amoral and vindictive, as a sort of gift to both Selina and Bruce. That action sparking the whole redemption arc of Selina that eventually began to happen in the bat-related books as written by Brubaker and Loeb. All so Batman would be suspicious if Selina had become a better person naturally or because of the Zatanna's rewrite, thus ending the blossoming relationship between them that beginning to happen. Then you had Dini setting up Zatanna's redemption and relationship with Batman in his Detective Comics run.
Editorial, of course, derailed that and went back to working on the Batcat stuffs in Detective Comics. So a big part of that was to use the Catwoman book to clear the air about what Zatanna did or did not to Catwoman, the whole Sam Bradley's baby thing that was done by another writer in the Catwoman book, and get Zatanna the hell away from Batman. So in the story Selina kicked Zatanna's ass, Zatanna revealed that she didn't change anything in Selina's mind to make her be good, that it was all her, and Zatanna convinced Selina to not wipe her memory, just accept that she did right by the baby giving her up to adoption.