Any currency or commodity has perceived value, because people gives it value. Why do people want to use a little piece of paper to buy a cup of imported coffee from a coffee shop? Why does the coffee shop vendor want that piece of paper? The simple reason is that people believe that the piece of paper are backed by the government and the government guarantee it's value.
In Bitcoin people can use the token to transfer value globally, because the token has a perceived value that are determined by supply and demand on a open market. ^smile^
This is the good explanation of how money used for the convenience of every people, thinking how to spent it and earning it is like giving yourself a privilage to decide and to understand the importance and value of every resources you have, Bitcoin is like that anyway.