What advantage do physical objects have as source of cultural information?

Physical objects reflect the cultural information for a very long period of time and display the actual picture of a culture passed in the history. For example when someone digs up an ancient culture's pottery, it reflects many aspects of the said culture, while one cannot reach the ideas or thinking of people who have passed in the same culture. You can dig up physical objects not the minds for cultural information.

each played a major role in ending the cold war.