Every artifact deck running around right now desperately wants their artifacts in the graveyard, and therefore, burying them free of charge doesn't hinder your opponent as much as it helps them. Secondly, the list with 4 Akroma and 4 Spirit is quite terrible against Oath because of the Legend rule (plus the fact they have counterspells).
As a side note, you are going to be screwed by Chalice for 1/2.
Pure discard simply doesn't have the depth needed in the metagame today. As soon as a threat hits the table, you are basically done for.
There's a reason Mono-Black is dead.
