Smart call divert : Users can talk on one SIM, and the calls to the second SIM can be automatically diverted to the first SIM. I fail to get a use case for this but I am sure there will be many uses.
Smart call back : If one SIM is in roaming and other SIM one is on home network, and the user gets a call on roaming SIM, this facility initiates a call back from home network SIM. You don’t have to tell the person to call on a different number. The phone intelligently takes care of it. Useful feature.
Sniffer program : Can track a mobile phone in case of theft and loss. This is available with quite a few phones.