If it helps to imagine it, think back to this scene from Captain America: Civil War. The impacts keep ending up all around our hero but never actually hitting him. Each time he passes across the minigun's line of fire, there is no bullet because of how slow the rate of fire is. Far, far slower than a real minigun fires.

Compare that to The Matrix where the minigun is depicted as firing so rapidly that not even an Agent can dodge it. This is a much more realistic depiction of the firing speed. (Althugh the rate of fire depicted varies considerably within the clip)

Bonus: In the Captain America clip you can see the minigun spin up to a speed much faster than it is actually depicted as firing.

Slower rate of fire puts more space between each bullet which results in a gap that the enemy aircraft can safely pass through. The goal is to basically make a box of bullets in front of the enemy plane that is tight enough that the enemy plane has to hit one and large enough that the enemy plane can't avoid passing through it. Decisions like rate of fire are an attempt to balance these factors.