Well it is not so no-brainer.
Just look at laser pistol or rifle, it is firing single shot. Maybe it will overheat with more rapid fire, maybe capacitator need to recharge or it takes some time before pistol generate laser beam. Maybe technology ditn't solve these problems, so more engeneered solution had to show.
This is solved by rorating capacitators and laser-production chambers. When it is in -90 degrees before it can fire, gattling computer give order to laser-chamber to produce laser beam. When it is in firing position, on 0 degrees, the laser beam leave the laser chamber and fire at target. Then imediatly it start to recharge and after 270 degree it is ready to fire again.