For the filter to work as expected (i.e. present only the items that meet the filter criteria) you must also update the CAML in every list query template or site filter in the report so that it references the filter name.
Specify an optional default value. With Choice filters, if you specify a default value that does not exist in the list of values, this value will be displayed in the menu when the report loads. This allows you to insert text like "Select Value" in the menu.