You can use the attribute if you want your code to do overloading.
[ActionName("MyOverloadedName")]
But, you’ll have to use a different action name for the same http method (as others have said). So it’s just semantics at that point. Would you rather have the name in your code or your attribute?
Phil has an article related to this: http://haacked.com/archive/2008/08/29/how-a-method-becomes-an-action.aspx