Null Rod is strong against Izzet Affinity's artifact mana and card flow. It shuts off Mox Opal, Seat of the Synod, Lotus Petal, Chrome Mox, the Baubles, Tormod's Crypt and Skateboard's equip, since those are all activated abilities of artifacts. It does not stop Urza's Saga (an Enchantment Land), Emry's tap ability (Emry is a creature, not an artifact), or Kappa Cannoneer's improvise (a static ability of the spell), so don't count on it against those. Surgical Extraction can exile every copy of a Mishra's Bauble, Urza's Bauble or Thoughtcast from their hand and library once one is in the graveyard. Static Prison targets a single permanent and doesn't keep up with their wide artifact board, so it's cut for more impactful disruption. Goblin Bombardment is low-impact in this matchup, so both of those slots are better used on artifact hate and graveyard disruption.