That’s actually a very informative data point. If you use headphones, you probably like to use music/video streaming services or play games. The longer they’re connected, the likelier you are to pay for your media consumption. You probably also have a bigger connection to your media device (a source of entertainment and happiness), so you likely also use and pay for other related products or services. If your headphones use Bluetooth, you have a newer device and set of headphones, so you probably like to keep up with tech trends and buy more expensive hardware, especially if your listening time is long.

That’s all from just looking at your headphone and Bluetooth status. Combine that with your device & vendor ID, contacts, location, medical and financial information, and all the other “sensitive information” they collect, and you can imagine how much information they can actually infer about you. That is their product: tailor-made targeted advertising and manipulation.

Disclaimer: I don’t want to do advertising for surveillance capitalism, so I would also like to add that the data they infer about you (political ideology, sexual orientation, etc.) can be completely false. However, there is no way to verify that (only you can do that anyway). Meta doesn’t care if the data is perfect. All they care about is that advertisers continue to believe that they provide the best dataset.