The GFW is about logging, mining, and controlling Internet traffic and data but your comment is about phone calls. These two things are only loosely related.

The article purports that the GFW is able to track electronic documents so closely that it can tie them to an actual individual. Assuming that’s true it positively refutes the notion that the GFW is “futile”. If the article and data leak are accurate then we also have proof that the GFW has the capability to detect many kinds of VPN and potentially decrypt the data streams. That is not “futile”, it’s scary AF.

Specific to phone calls you and your Aunties can chatter about whatever you like but there’s a strong possibility that those calls are being recorded, transcribed, and reviewed by automated systems for potential real world action. We know that the American NSA has this capability so it’s a near certainty that the Chinese Government does as well.