The Himalayan Rescue Association, a non-profit health organization that offers safety seminars to trekkers in Manang, warns that ascending more than 300 or 400 metres higher than the previous day's sleeping altitude is not safe, especially when you are above 3, 000 metres.
Not only does this feature allow you to engage in truly personal listening (perhaps your partner is sleeping in the next room?) without shelling out for an expensive pair of wireless headphones or dealing with their often-complicated set-up, but it opens up a whole range of creative use cases and possibilities for future features.