Using a function to define javascript objects

Question

Hello, like to ask if the  external parenthises are really necessary?   Like here:
incident.Controller = (...)     //see code block at the end of this question
 I dont think so.   (at least the code works the same for me).
Also, I would also like to know the difference between the two snippet of code below.
The benefit writing the code below in a function (the first snippet below) is to scope things to myCompany.incident by using the "use strict" statement.  Like below. Right?  (i would otherwise write it out as in the snippet beneath
it)
myCompany.incident = (function(incident) {
  "use strict";
  incident.Contracts = {
    onLoad: function() {
      var controller =
              new myCompany.incident.Controller(Xrm);
      controller.load();
  return incident;
}(myCompany.incident || {}));
I would otherwise (if not for "use strict";) write it out like this:
   myCompany.incident = myCompany.incident || {};
   myCompany.incident.Contracts = { onLoad: function() {
         var controller = new myCompany.incident.Controller(Xrm);
         controller.load();
I dont think "use strict;" is the only difference/consquence of the two snippet, which is the reason for this question.
Thanks, p.
/// <reference path="controller.js"/>
/*global myCompany: true*/
myCompany = window.myCompany || {};
myCompany.incident = (function(incident) {
"use strict";
incident.Contracts = {
onLoad: function() {
var controller =
new myCompany.incident.Controller(Xrm);
controller.load();
return incident;
}(myCompany.incident || {}));
Thanks, Paul

Answer 1

There is an application report that give you a listing of your region source and allows you to search the source and gives you links to edit it.
Application Reports>Page Components>Search Region Source
So you shouldn't have to keep it in a separate file.