Jeskai Artifacts relies heavily on activated artifact abilities from Goblin Welder, Goblin Engineer, Emry, Lurker of the Loch, Mox Opal, and Urza's Saga, so Null Rod is extremely effective, shutting off Mox Opal's mana ability, Emry's cast-from-graveyard ability, and Urza's Saga's token-making ability. A second set of Fatal Push cleanly answers their cheap creatures like Goblin Welder, Goblin Engineer, and Emry, all mana value 2 or less, slowing their engine before it starts. Mockingbird is a weak copy target against their small utility creatures, and Wail of the Forgotten's descend 8 is hard to enable while trying to disrupt their fast artifact engine, so both are cut.