Puzzler makes it easy to insert bits and pieces of Wikipedia content into Drupal, keeping the information fresh as improvements are done by the community of Wikipedia editors.
Other modules that provide integration with different Yandex services may require this module to get user's access tokens.
Basically as a site builder you need this module only if another module depends on it. As a developer you may add this module as a dependency of your one if it needs user's Yandex access tokens.