It matters because she breaks into a compound, kills a few soldiers, makes a crap ton of noise, puts on a visual spectacle with a glowing lasso, and no one sees a thing, even though the base is crawling with people.That just doesn't make sense.
He is trying to win Diana to his side. He does it by admitting he interfered. She saw through the, "I only gave them the idea" thing super easily. This isn't exactly Darth Vader trying to win over Luke.
Yes, its flammable. It is also flammable on the ground, but they say they can't blow it because it will take out 50 square miles. That wasn't a 50 square miles explosion in the sky.