What is the price of a cup of Coffee in Germany? Less than 3 dollar I guess. The transaction charge of BTC could be more than the tax of a coffee cup. Not wise though to pay BTC for a cup of coffee.
Yes ,it is true that the transaction fee maybe bigger than the coffee itself and using your bitcoin maybe a stupid decision but if you look on the big picture this is a start of something big. If a first world country can implement this probably other countries will follow until we realized that we can buy a car using bitcoin without taxes.
As of now on our country the tax is 12% if you buy something and actually bigger on cigarettes and alcohol. Imagine how much we can save if we purchase a house or a car using Bitcoin.