Then why put a machine gun on a flying drone at all? It does have to aim... A machine gun is going to be shaking after it starts firing. A sniper rifle just needs one shot. At night they're not going to see it up in the sky so it can be anywhere close enough to get off a shot and adjust for the next one. If you watch footage of drones flying during the day light carrying explosives, the enemy doesn't know they're there until the last moment. Look at Hezbollah drones flying over Israeli strategic sites. The Israeli military didn't even know about it until it posted on the internet. At night it makes it even more difficult to spot.