JS - Why do you need 2 intermediaries when inheriting

I am reading a tutorial, and I don't understand the logic behind this:

function inheritPrototype(childObject, parentObject) {
    var copyOfParent = Object.create(parentObject.prototype);
​
    copyOfParent.constructor = childObject;
​
    childObject.prototype = copyOfParent;
}

So I understand that there needs to be an intermediary because if you did child.prototype = parent.prototype; any changes to the child would be done to the parent. But that's done in Object.create(parentObject.prototype); So why does there need to be another intermediary?