For example, an opponent who gained 2 life and lost 1 life in the same turn still lost life
Most card bannings are often the result of a mistake from Magics design team, and these cards are no exception

Sort Card Type Karrablast #8Common $0.22 Karrablast #9Common $0.28 Karrablast #6Common $0.18 Karrablast #8Common $0.14 Karrablast #7Common $0.13 Karrablast #12Common $0.13 Karrablast #8Common $0.04 Karrablast #15Common $0.07 Karrablast #9Common $0.18 Karrablast #9Common $0.08 Karrablast #7Common $0.09 Karrablast #3Common Karrablast #1Common $0.10 Karrablast #3Common $3.00 Karrablast #8Common Karrablast - 009/086 #9Common $0.07 Karrablast - 009/086 (Master Ball Pattern) #9Common $2.87 Karrablast - 009/086 (Poke Ball Pattern) #9Common $0.36 Karrablast - 094/086 #94Illustration Rare $19.52 Karrablast - 094/086 #94Art Rare $8.50 Karrablast (Master Ball Pattern) #9Common $2.77 Karrablast (Poke Ball Pattern) #9Common $0.27 Karrablast - 094/086 #94Illustration Rare $19.52 Karrablast - 094/086 #94Art Rare $8.50 Karrablast #3Common $3.00 Karrablast - 009/086 (Master Ball Pattern) #9Common $2.87 Karrablast (Master Ball Pattern) #9Common $2.77 Karrablast - 009/086 (Poke Ball Pattern) #9Common $0.36 Karrablast #9Common $0.28 Karrablast (Poke Ball Pattern) #9Common $0.27 Karrablast #8Common $0.22 Karrablast #6Common $0.18

This mid-game ramp card keeps the mana generation coming even if you run out of land drops, which sets up for huge turns, or takes care of all your artifactfall needs
Before aggressively scaling UA, ensure that: Even a 510% lift in store CVR can materially reduce blended CPI and accelerate ROI recovery
This build was fairly casual, but I could definitely see an all-in Swords build with the best equipment in the game working really well