JavaScript: Comparing a closure with and without IIFE

Hey,

If I use a closure inside an IIFE like this:

var outerFunction = (function() {            // this is an IIFE
  const outer = `I'm the outer function!`;

  var innerFunction = function() {
    const inner = `I'm the inner function!`;
    console.log(outer); // I'm a variable from the outer function!
  }

  return {
    kir:innerFunction
    } 
})();

Code (markup):

It seems to me that the IIFE returns an object called outerFunction and add the method kir to it.
So that now, I can access the kir method of the object outerFunction with the following code:

outerFunction.kir();

Code (markup):

But if I don't use an IIFE for the same example:

function outerFunction () {
  const outer = `I'm the outer function!`;

  var innerFunction = function() { 
    const inner = `I'm the inner function!`;
    console.log(outer); // I'm the variable from the outer function!
  }

  return {           
    kir:innerFunction
    } 
}

Code (markup):

I can access the method kir only if I run this:

outerFunction().kir();

Code (markup):

Why it doesn't work if I run this?:

outerFunction();
outerFunction.kir();

Code (markup):

It seems to me that in the first example, when the IIFE runs automatically, it returns the object outerFunction and add the method kir to it.
But when I run outerFunction manually, it's different and I can't access the method kir.

I'm a bit confused!
Can some one please explain to me why I can't access kir method in the second example by running this?:

outerFunction();
outerFunction.kir();

Code (markup):

I guess this is more a question about understanding IIFE rather than the closure.

Thanks