Because Itachi is a fan favorite. Not many people want Sasori, Konan, or a lot of other ninja's. But they do want Itachi. And when an event like this happens where you can get him. People go nuts just for the fact it's Itachi. Yeah I got Konan, Threads, and Stamina Pots, and a few Sasori Frags. But Itachi was the main point of doing the event. And so is a lot of other people's reason's.