If those 3 guys in charge are the bottleneck of Al Queda, then it's a serious blow to terrorism. But terrorist networks operate with independent cells, their bottleneck being more about resources and less about leadership. Freezing bank accounts, shutting down operations that are financing terrorism does a lot more good than the killing of Bin Laden.

In the case of spam, banks know when transactions are made for fraudulent products. For this whole industry to work you need their cooperation as online transactions are only possible through banks.

Take this away and I could see spammers in real trouble.