Why is the BinaryFormatter's output human-readable?

     public static void Save(GameData _data, string _fileName) {
         string filePath = Path.Combine(Application.persistentDataPath, _fileName);
         //Debug.Log(Path.Combine(Application.persistentDataPath, _fileName));
 
         BinaryFormatter binaryFormatter = new BinaryFormatter();
         FileStream fileStream = new FileStream(filePath, FileMode.Create);
         binaryFormatter.Serialize(fileStream, _data);
         fileStream.Close();
     }

^ There's my code that serializes one of my classes into binary... but when I browse to that binary file and open it in notepad... it looks like this...

 {"strength":-3,"defense":-3,"speed":-3}

Am I crazy? That doesn't look like binary... more like... JSON... ???? 0_o