A good compromise. When 20000 people have a great time watching a scheduled event that seems fair. Peeps can make preparations to participate or avoid.
I'm not ok for every kid in the neighborhood having access to little explosives.
Backyard rocketry is imo something to be celebrated, a bit less if it's just buying premade fireworks, but kids learning chemistry and engineering in an exciting way isn't bad- it also helps with developing a sense of responsibility when you will probably mess up and hurt yourself