'Good Friday' is a holiday in over 135 countries and 12 states. Most of those countries observing the important holiday still have secular state with seperation of church and state like the United States, and in some countries Christianity is even a minority. The U.S. is currently the only western nation not observing 'Good Friday' as a national holiday, despite 80% being Christians and having the world's largest Christian population.
'Good Friday' should also be declared as a holiday because there are no holidays between President's Day in February until Memorial Day in end of May. So 'Good Friday' will be a perfect holiday in between, and will create a three day long weekend. The holiday still have secular aspects and not really religious anymore.