Most games have extensive code that can’t use JUST Babylon. How much of the actual code goes inside the createScene() function?
Sorry for the long delay before a reply.
The createScene method is a useful way to set up a scene, particularly to transfer the scene to the playground. It is just a function like any other JavaScript function, a convenience no more. You are free to set up functions in any manner you choose. As for any function it is all a question of passing the correct parameters.