Javascript - self-executing functions : why to use them if I can create local scope with not self-executing functions?

I know there are a lot of posts here and elsewhere about selfexecuting functions but I still have some questions after reading posts.

1. why would I ever assign a self-executing function to a variable? If seems that they execute themselves anyways.

   var myFunc=(function() {
    console.log('Hello World');
   })();
   

2. I read a lot that the reason to use self-executing functions is to keep variables private. If I have a not self-executing function, everything I define inside that function is gonna be private anyways?!

   (function() {
    var name="my Name"
    console.log(name);
   })();
   
   vs.
   
    function() {
    var name="my Name"
    console.log(name);
    };
    //its the same
   

So I dont quite understand how self-executing functions are to keep local scope (as you can do that using not self-executing functions) so the only reason I see is to use them when you want to execute automatically for example on page load.

Thanks!

just one more question:

var test=(function myFunc(){
      var name="Hello World"
      return {
        test1: function(){
          return name;
        },
        test2:function(){
          return name+"1"
        }
      }
    })()

    test.test1()

vs

    var test=function myFunc(){
      var name="Hello World"
      return {
        test1: function(){
          return name;
        },
        test2:function(){
          return name+"1"
        }
      }
    }

    test.test1()

--> what exactly happens here that because of IIFE I can actually execute test.test1() and not with a regular function?

You usually wrap your functions in a anonymous function when you want to keep your scope contained. This is also part of the module pattern which is still pretty popular:

https://toddmotto.com/mastering-the-module-pattern/

Then you can assign the outcome of that IIFE to a variable so your scope can only be accessed by calling that variable.

myScope.myLocallyScopedProperty or myScope[myLocallyScopedProperty]

Your other function needs to be called manually and it also accessible from anywhere.

I suggest reading the article by Todd Moto it explains a lot.