One of the main advantages is full flexibility. You have a total freedom of movement. You can go anywhere you want with your small gadget.
The market is full of different devices from dozens of companies. Their competition is so fierce that it pushes the development of this industry by leaps and bounds. Every new device is better and better. In some 10-20 years we have all the odds to minimize physical materials developing "goodies" of the 21 century.