We don't. However, being able to wear technology rather than carry it around means that it is usually much more convenient. You can think of wearable technology as akin to a pair of glasses. Once put on, most people forget about them. Indeed, they can become part of an individual's identity. Compare that to carrying around a pair of lenses in your pocket only to use when they are needed. In short, though wearable technology may not be essential, it is extremely helpful.