Its very very useful in Mirror matches.
Since M'sia majority is BF lets say you should seriously sidedeck it.
Graverobber could be useful in a BF mirror match.
Steal their Black Whirlwind (frigging epic , no?) , steal their Cards for Black Feathers, steal their Heavy Storm, bla bla bla.
While doing this, you could force them to waste their DD Crow on their card. Now they cant Crow your Blizzard target, and your Vayu! yay!
I will be extremely surprised if anything besides BF tops M'sia tourney. All the more knowledgable players are choosing BF as their deck of choice.
But the variants and card choices are all gonna be extremely different.
Simply put, this format is an Oppression format.