Yami, Black and Magical Girl Kyoko were the way of giving something to Black Cat fans while they wait for the continuation that Hasemi Saki and Yabuki Kentaro said they would like to do someday. Something similar to what happened with the cameos of TLR in MNO.
I also prefer Momo over Yami. I only like her when she's with Mikan.
Seems I'm the only one here too who's going to miss Haruna
I'll have to conform with the anime :/