Depends on the case. If you already know who belongs to a terrorist organization then maybe stopping the money and limiting the ability to terrorize would be a higher priority.

Well, it looks like a lot of this is designed to make the job of law enforcement easier because politicians that seem "tough" on crime have better election prospects. Freezing the money is far more dramatic and provides nice numbers for said politician's re-election campaign.

Sometimes the people who own that money are out of jurisdictional reach.