Nevertheless it is risky to put these Graveyard-interacting cards in your "Gravekeeper's" Deck because without "Chief" on the field they are complete dead draws.
However, keep in mind that because "Chief" unlock access to your Graveyard, your opponent can also exploit it for activating their "D.D. Crow" or "Kycoo the Ghost Destroyer", so be very careful.
Although somewhat illogical, "Gusto" Decks can also exploit this card (mostly in anti-meta builds) for locking down opponent's options. This is useful against other Graveyard-based Decks, while still leaving "Caam, Serenity of Gusto" and "Daigusto Gulldos" activate their effects safely. This can be done since both of their shuffling effects are costs, which unaffected by "Necrovalley".