I was imagining if back in ye olde days (say 1800s) when one doesn't have a calendar and is already having a fleeting grasp of time, it might have been a lifesaver to hear a bunch of fireworks because one would be sure it was either one of them pyrotechnically active holidays (4th of July, New Years Day).

Kinda in the same way a noon gun works to say LUNCHTIME! or church bells sing SUNDAY!