Headphones are important sometimes.  They allow me to listen to an audio source without anyone nearby hearing.
Yes, I agree. They are especially useful when travelling on a bus or airplane.
Headphones
Headphones (or head-phones in the early days of telephony and radio) traditionally refer to a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air for anyone nearby to hear. Headphones are also known as earspeakers, earphones or, colloquially, cans. Circumaural (
's response at frequencies lower than 20 Hz is typically very small. 
Headphones are also useful for video games that use 3D positional audio processing algorithms, as they allow players to better judge the position of an off-screen sound source (such as the footsteps of an opponent or their gunfire).
Although modern headphones have been particularly widely sold and used for listening to stereo recordings since the release of the Walkman, there is subjective debate regarding the nature of their reproduction of stereo sound. Stereo recordings represent the