Is there any point in having CCTV ??

I see CCTV all around London...It definitely feels like all eyes are on me...and then I think..well thank goodness... no one can harm me because they know cops are watching...or cops are probably not watching every second but they have the tape..everything will be on tape. This feeling might be shared by millions. But last week, my friend went out at night, just to get a few essentials from a shop down the road. It was crowded. Suddenly a bloke ran from behind her , turned around and blew a punch on her jaw..and ran. No one came forward obviously. The incident was reported to police , of course. What happened next are as follows. The cops called her every 24 hours, asking about the incident, taking statements and promising to have a look at CCTV for that time. Week passed and the result was, my friend was given a few advice. For example if something happens, she should call cops that instance,and they will turn their camera in that direction ...and not wait to go home and try to put ice bag on face before she rings...how ridiculous is this. For your reference, no arrests were made and her face is still swollen. So a question...is CCTV there really ensuring public safety and crime prevention. Or is it just for show...giving false hope we are safe...