It's use of rockets is pure genious.

If I compare it to its previous weapon of choice, which was suicide bombers, it is a much better terror weapon.

Why ?

1. It covers a much larger area.
2. While suicide bombers are scary, you could avoid them with high probability if you avoid crowded places, such as buses and cafes. Rockets make you nervous in your own living room. All the time.
   3.Rockets have a lower body count, and if there is something the international media gets bored with, it is a low body count.

So you got a lot of the Israeli citizenry, under constant threat, pushing the government to punish Gaza for those puny missiles. Any response would be 'unproportional'.