The headphone cables tether you to your phone. There are times when you want to be able to put down your phone and be able to use headphones but not be physica

The headphone cables tether you to your phone. There are times when you want to be able to put down your phone and be able to use headphones but not be physically connected to it. Eg lying in bed listening to music, but then getting up to go to get something from the kitchen (and not having to pick up your phone, or carry it with you, or unplug the headphones) before lying back down again. And being able to do that while continuing to listen to the music. Routers need to be plugged into a wall socket. Batteries don't require that constant use of a cable or socket.