The past two nights I saw two movies (which is incredibly rare this past few years for me)

La belle verte (1996) and The Day the Earth Stood Still (1951)

In both movies, someone from a more advanced civilization comes to earth - from another planet - to witness some nonsense and craziness of earthlings.

In both movies the visitor uses some hard "money", like gold or diamonds and is surprised that on earth they do not anymore.

...