The best answe is It allowed revolutionaries to seize guns and ammunition.
The Bastille was an old medieval prison in Paris that became hated because it symbolized the power of the rich. By 1789, trouble was brewing in Paris. The ordinary citizens were angry at the power of the nobility. On the July the 14th, 1789, a group of protesters rushed to the Bastille to remove the weapons stored there, at the time, over 30,000 pounds of gunpowder was stored at the Bastille. This started a fight between the prison guards and the protesters. Fighting continued for a few hours until the governor of the prison surrendered.