Yes; by comparison, Vulcan rounds are extremely cheap versus guided rockets (tens a dollars per round versus hundred thousand dollars plus per missile), so if you have a low threat engagement like a sniper in a house in Afghanistan it is very effective to shoot 50 cannon rounds at it. Same for a small truck convoy, a plane can get on the target faster than an attack helicopter just because it is 3 times faster at low altitudes.
It is not meant to replace an Apache or Cobra helicopter, but to occasionally take out ground targets.
The time is not the important factor, the number of shells on target is. These guns have very high rates of fire, dozens of shells per second. A plane can empty the entire cannon load in 5-6 seconds.
It is not meant to replace an Apache or Cobra helicopter, but to occasionally take out ground targets.