The Black Cat as /Negative/Follower is part of the tradition of the 2 or so "Unwanted Followers" like the Hag and the Poltergeist, and follows the style of American/European folklore that suggests Bad Luck when they "cross your path". It is a good balance to the many many other cool and helpful followers who can do something worthwhile for the player.
As I think about it, in many legends and tales Black Cats are usually the 'Familar' or an accomplice of sorts to Witches.
It might be cool to either have a house rule where if you are evil, the Black Cat, instead, gives you a Fate token, perhaps every time Night falls.
Alternatively this property or house rule could be used only for Evil *spell casters*
Alternatively, part 2, perhaps a future character or two could be a "Witch" (I know we have some as encounter cards, but don't think the title is used for any one character)) and to this character, the Black Cat can be taken by an encounter with someone who has it as a Follower, or similar device.
--- looks like I could ramble on a bit over the Black Cat!