1. Drone strikes only involve the target's life: the shooter is not risked. If the government is actually considering using these things against us (remember that they said that they would only use these on American citizens "in combat". Waco comes to mind as "combat" in their view).
2. The target is reachable anywhere - in their homes, on the road, on vacation, etc.
3. The attack is nearly always a surprise - another advantage for the shooter. Similar to a sniper attack but with even less risk.
4. There is virtually no defense against a drone attack. If they know where you are or even suspect it, you're hit. Hitting a drone first is almost impossible. While I was still on active duty, we had drone targets for our .50 caliber machingunners. Despite thousands of rounds fired and a lot of sincere application, none of the targets were ever hit.
This is the first generation of anonymous warfare. This is only the beginning.
Interesting that you fired M2s against drone targets. No hits obtained is not surprising. It is very tough to hit a point with a point. (My dad's unit had a 100% kill ratio against drones, but they were lobbing Nike Hercules's at 1960's era RCATs, not .50 ball at stealth Predators. I did get a nice drone propellor out of the deal.) If I wanted to fight a drone, I'd get one of these. It's not much, but it has more chance of hitting than a rifle.