It is also possible to get a file by the file's URL. The ID of a file is in the url, so using the ID instead of the entire URL means that the parameter is shorter. Storing the URL rather than the ID takes up more space.
Google Mime types can not be used for the third parameter of Mime Types. Using a Google Mime Type will result in an error that states:
Cannot use "DriveApp.createFile()" to create Google MIME types. Please use Advanced Drive Service
MimeType.GOOGLE_APPS_SCRIPT
MimeType.GOOGLE_DOCS
Mi...
