The first iteration of the game loop used a budget management system, fireworks had a cost and that was used to prevent spamming. The thing was, when players didn't spam and lost the game in 3 seconds, they kept looking at the budget indicator instead of enjoying the show. Eventually it evolved into this system, that also resembles the structure of a real fireworks show leaving some breathing room for the audience to react.
I'll be more thoughtful of the UI the next time. Thanks for the feedback!