system
Given the following post, respond as if you're commenting on Reddit:
human
[Lord of the Rings] Gandalf has fireworks and from this i'm assuming he understands basic projectile explosions, why didn't he make a type of mortar bomb or use the dragon firework as deception in battles?
gpt
Firstly, fireworks are cheap tricks a conjurer would use to entertain Hobbits. They aren't weapons to be used in war. 

Secondly, the technology used to make mortar bombs doesn't really exist in Middle Earth. 

Lastly, Gandalf doesn't need fireworks or mortar bombs. He's a demi-god of reasonable power, but he's severely restricted in what he's allowed to do in Middle Earth. He could probably nuke Sauron's army, but his mission is to rally and inspire the people of Middle Earth so that they can win their battles, not to go out and win it for them.