Why telephone cable is a COIL cable?

The telephone cable is coiled, which makes it easy to extend, much like a spring. By the coil-like figure, it seems very short length but still be able to be pulled for a much long distance. The operation radius is increased. With it, people can move more freely when they answer the phone. Not only telephone cable, but also POS machine in the shopping mall, is equipped with coil cable. The coil cable is so much flexible and retractable. It realizes the fact that, it is convenient for people to answer the phone or operate the device from a longer distance, on the other hand, the cable will not messed up when you come closer to the telephone or device.