If you think about it, now it makes sense why big names in smartphone industry like Apple and Samsung are removing P2 plugs from smartphones in favor of more powerful interfaces like Lighting/USB-C: so you can track more information about the user.
Just imagine: you can track which kind of phone a user that likes to listen to Heavy Metal, for example, likes to use, or which phone is more popular at the moment. Based on this you can develop phones that is more likely to sell or use specific marketing campaigns depending of the kind of music a person listen.
There's a much more mundane explanation - waterproofing. Lightning and USB-C connectors can both be made intrinsically waterproof up to IPx7, while the 3.5mm jack can't. Waterproofing is a key point of differentiation for recent flagship phones. An iPhone 7 will survive a dip in a toilet bowl or a pint of beer, but an iPhone 6 probably won't.
I had a Xperia Z5 and every time water touched the headphone jack the phone would go crazy thinking that I was plugging and unplugging something repeatedly.
I don't see the difference in the connector and how that can determine how waterproof the phone is. In the end, lightning/usb-c and 3.5 are just sending electron via a connection, how would the format determine how waterproof you can make it?
To all the people saying "but waterproof 3.5mm", here's the thing. Despite having _more pins_, lightning and USB-C have the advantage of _active signalling_. So not just an "open/closed" signal, but an active communication saying something was plugged in. So while 3.5mm can be made where it doesn't damage the phone, water will still short the open/closed switch, causing false insertion events.
There is a lot of conjecture happening here. I'm sure it doesn't hurt to know data about headphones but I'm having doubts that's the primary motivator.
Yeah, I am not saying this is happening right now (however this log from Spotify is alarming).
However, considering that they will have this option is sufficient to someone in the industry to abuse it, and after someone start to use this information, everyone will to remain competitive.
So all a device needs to do is play sound and they can retrieve you bluetooth make, model, and serial number. There's your replacement for the unique ID that Apple supposedly killed years ago. They just need to look at your bluetooth device identifier.
Just imagine: you can track which kind of phone a user that likes to listen to Heavy Metal, for example, likes to use, or which phone is more popular at the moment. Based on this you can develop phones that is more likely to sell or use specific marketing campaigns depending of the kind of music a person listen.