Although that fact is disputed.
It has been claimed that this battle, which occurred near Crécy in northern France early in the Hundred Years War, marks the first use of cannon on the battlefield. Like many claims that reach us through the mists of time, this one is hard to verify and is oft disputed: According to Arab historian Ahmad Y. al-Hassan, the Mamluks employed the “first cannon in history” against the Mongols at the Battle of Ain Jalut in 1260. In the end, it may come down to how the word “cannon” was defined in those days.
It wasn't very effective then but it sure has been throughout the ages. Artillery was the queen of battle until the advent of the airplane. I think the self-propelled artillery piece will still be needed even a few centuries into the future.