Abrade destroys key artifacts like Pinnacle Emissary or Chalice of the Void, and its damage mode can also kill Emry, Lurker of the Loch, which is a 1/2. Note that Kappa Cannoneer has ward {4}, so targeting it costs extra. Disruptor Flute can name Kappa Cannoneer to make it cost {3} more, or name Urza's Saga to shut off its Construct-making ability (the Saga is a land, so naming it never taxes a cast). Flusterstorm is weak here since it can only counter instants and sorceries, and their deck is mostly artifacts and creatures, so we prioritize proactive artifact hate instead. We still want to resolve a fast threat before their board of artifact creatures overwhelms us.