The twilight had passed, and the sky quickly darkened.
In the sky, the continuous bursts of fireworks took the place of the setting sun.
These fireworks would go on until the banquet came to an end.
This signified that the birthday celebration was about to start, and the guests took their seats.
It was also a kind of universal ritual. Just as lighting candles on a dining table or illuminating one's house with light can be seen as summoning 'purification' with 'light'; adorning one's house with artwork can be seen as 'art' protecting 'nobility'.
And a grand firework display could satisfy the realms of "light," "art," and "fire" of three True Gods, thus receiving the blessings of Mr. Radiance, Yawen, and the God of Fire.
Such a universal ritual is definitely not completely ineffective. But in reality, it's just a way to feel at ease.
Nevertheless, fireworks are not overly complex transmuted objects.