The article implies that the cameras were installed against terrorists. Some people are pretty happy to throw their privacy away in this illusory fight against terrorism. Needless to say, the terrorists have already won, we’re slowly giving up everything that separates us from them.
They have security cameras to protect people and the bank assets - not do monitor the work of their employees.
At least in Europe that's the law. Besides that, you must have visible warning signs to let people know there are cameras recording them, and you also have to notify the national entity that's responsible for data protection that you will have "X" cameras (image, audio, or both) for the "Y" purpose.
- For security reasons: to protect people and assets;
- For monitoring: to control your employees activity.
Picking a ridiculous example: if your boss tells you that you're spending too much time talking/doing a task/eating, because he as been watching you via security cameras, he will be in a lot of trouble.
If it's the second, that's ilegal in a lot of countries.