On keeping your husband's name after divorce

Why do some women keep their husband’s last name after they divorce him?  Is it because they are having fantasies of a reconciliation? Or is it because they think his last name is better than theirs? Or could it be that they want to have the same last name as their kids? Or maybe it’s because they are just lazy to change all the paperwork like passports, social security cards, and other forms of I.D.?
I find it very curious when a woman keeps her husband’s last name.  Some of my friends have done it; and surely there are public figures like Ivana Trump who do it. With public figures like Ivana, however, it is almost understandable since the Trump name is so bankable. But why do other women do it? Especially when their husbands have moved on and married someone else. So now there are two women walking around with his last name.
It is a very curious thing.