Also there are some things that you just cannot shoot live... In CGI you can change the laws of physics, for example, you can bring people to live that have die

Also there are some things that you just cannot shoot live... In CGI you can change the laws of physics, for example, you can bring people to live that have died centuries ago, or create imaginary world that are limited only by the human imagination - something that has been shown to be immensely capable.