The purpose of a waterproof walkie talkie is to guard the actual device, the radio, from water damage. An electronic device cannot function when wet or waterlogged, but devices that have the capability to protect themselves against water ensures that you can communicate with your friends in any weather condition or terrain. If you are planning on using a radio on a boat, it is especially important to factor in a level of waterproof protection to ensure that an accidental splash or drop does not ruin the device.