The caplock method of firing shortened the time needed for the fire to travel from its ignition to the gunpowder.
This was useful in hunting, because it give game, after being alerted by the snap of the gun, less time to escape.
More important in warfare, the mechanism was also easier to load.
It made rates of fire of 2 - 3 rounds per minute possible.
Also it was far more reliable and water-resistant than the flintlock.
Besides use in muskets, the caplock mechanism enabled the development of revolver pistols, which appeared about a decade after the caplock.
War Matrix - Caplock
First Industrial Revolution 1750 CE - 1830 CE, Weapons and technology