What are the pros and cons of laravel disk file sytem over tradional file system ?

You get a lot of flexibility without having to change your code. For instance, you can store a file on your local server, or a remote sftp site, or an AWS S3 bucket and still use the same kind of code, eg :

Storage::disk('avatars')->put('file.jpg', $contents);
Storage::disk('audio')->put('file.mp3', $contents);

If you needed to move your 'audio' disk from a local one to amazon S3 - it would be quite easy and your code wouldn't really change. Compare it to doing it by hand and you can see how it makes life easier :-)

Is there any scope to hide my file folder or directory of images ?

Yes - it's covered in the docs : https://laravel.com/docs/5.7/filesystem#file-visibility