>>52924701If it takes 2 flamethrowers to ko but only one fireblast then fireblast is better.
Winning in one turn 85% of the time is much better than winning in one turn 0% of the time.
BP of moves is also a multiplier rather than additive so even a 20 BP difference is enormous.
Unless a pokemon is a setup sweeper giving up some accuracy for higher damage moves is often superior. To a point at least. Flipping a coin with zap cannon is still a bad idea.