To avoid confusion! If all deserts had the same name, nobody would know what area was being referred. Were they referring to a desert in China or in the United States?
Haiti has no deserts.
There are no deserts in Delaware.
Japan has no deserts.
There are no deserts in Rome.
Honduras has no deserts.
Alaska has no true deserts.
Alabama has no true deserts.
There are no deserts in Ireland.
Kentucky has no deserts.
There are no deserts in Kentucky.
Yugoslavia has no deserts.
Haiti has no true deserts.