Mono-Blue Faeries relies on a swarm of small creatures like Faerie Seer, Faerie Miscreant, Spellstutter Sprite, and Moon-Circuit Hacker, so Fiery Cannonade's 2 damage sweeps almost their entire board of 1-toughness and 2/1 creatures in one card. Rooftop Percher flies over to block and race while gaining life. Relic of Progenitus offers minor incidental value but is cheap enough to include. Crop Rotation and the extra utility lands are cut since this matchup rewards proactive board sweeping over land fixing, and their deck has no meaningful graveyard plan for Bojuka Bog to interact with.