Even in a language that has a relatively rich syntax, like Ruby, treating nil as false can make code more concise and understandable. For example: hash[key

Even in a language that has a relatively rich syntax, like Ruby, treating nil as false can make code more concise and understandable. For example: hash[key] = value if !hash[key].nil? Can be written as: hash[key] ||= value And: response = find_resource(key) response.nil? ? response : not_found Can be written as: find_resource(key) or not_found I also can't think of any instance where a function has used an empty string to denote a failure condition. In a language that treats nil as being false, generally functions are quite careful as to the value they return.