It's called closure. To many this is all the closure they needed. It's a relief to know that we finally got him. Sure, he was more a figurehead or whatever, but it feels good to those who lost loved ones on 9/11. To some extent, it was what people criticized Bush for. "We didn't get Bin Laden, but we got 5 of his second in commands." So here we have the top man. Now the next time we take out one of Bin Laden's second in commands, we actually take out the leader. It's also a psychological boost. Bin Laden is the name we know. It's the name the world knows.
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson