It is used also as dummy pronoun, such as in it's me, and when referring to an animal or child of unspecified sex.
She was holding the baby, cradling it and smiling into its face.
As attributive, it is used to denote a person or thing that is exceptionally fashionable, popular, or successful at a particular time.
They were Hollywood's It couple.
So, yes, there is an exception to it being used only for objects.