Smartphone can be used to organize protests.
See: Hong Kong Protests (they didn't succeed in their goals, but still, they did put up some resistance)
Also, union activity. Encrypted chat apps to prevent employers finding out what you are up to. Prevents employers preemptively firing you before you get to legally form the union and get legal protection. Make strike-breaking harder.
Encrypted communications is very useful for people in abusive relationships. Smartphone cameras and microphone can record evidence of abuse. And data connection could also be used to save it to cloud and prevent deletion of evidence. Also, while not a "smart" phone specific feature, text to 911 is very useful if the abusive spouse is nearby and you need to call for help, and need to keep quiet. GPS positioning makes it easier for rescuers to locate you.