Technically speaking, as a "true" Gatling gun (fires all barrels in sequence, each barrel is at the same point when fired) this wouldn't be very impressive. Even speaking optimally, the Max RoF of a "true" Gatling gun is limited by:
Distance Traveled per shot = (Circumference of Rotating Barrel)/(Number of firing points)
RoF = (Rotational Speed of Rotating Barrel)/(Distance Traveled per shot)
So this would have to rotate very fast in order to hit the max RoF. You'd be hard-pressed to see a benefit to this weapon.
That being said...
If this were not a "true" Gatling gun, it'd have slightly more potential. It could perhaps fire multiple shots at the same time. It'd be great fun to watch, but not very useful.