Knowing that someone is spying on you is worth much less than knowing that they use Camera Model XYZ, which transmits on XYZ frequency and the camera is located at coordinates XX, YY.
Edit: To clarify, I'm sure Al-Qaeda already knew not to trust any computer, or cell phone that they used because they were probably completely compromised. So nothing that has been revealed by ES would change their behaviour.
Edit 2: Also, it doesn't matter. The most important thing for our civilization is not personal or national security but our democracy. A 'security state' is never democratic. Its people are never free.