Food allows me to stay alive -> it has value for me

Legal tender of the country I live in allows me to pay taxes and stay out of jail -> it has value for me

Please send me all Deutsche Marks you have. I will then go to the Deutsche Bank and exchange them for Euros :)

We should get rid of them since they have no value. Personally I like them because they facilitate trade and finance on a global, immense scale and allow for decentralised price discovery and information distribution. But then does trade and finance have value? ..wait maybe money networks do have value