Android Device Manager is supposed to locate your phone and do remote lock and remote wipe. Problem is the phone can be switched to aeroplane mode or shutdown without unlocking it with pattern / pin / password.
Data connection will be lost seconds after the phone is stolen. So what's the point?
There is two parts to it,
Cell phone is lost : Lets assume its lying somewhere or someone found it. In this case you can use the Device Manager to locate the location.
Cell phone is stolen: This guys are smart, they know the technology, they know the hacks. They will switch-off with cell phone as soon as they can. They will wipe out our data and most probably brick the phone. Not sure, but I think they even change the IMEI number to make it completely untraceable. In this case Device Manager or most security software is useless.
