I find it particularly amusing that you used the wrong pronoun while scolding me to use the correct pronouns for her.
If that doesn't prove the impracticality of using "it" as a pronoun, I don't know what does.
It breaks the rules of English that we all understand subconsciously, so it's difficult to do without consciously thinking about every single usage of a pronoun in a sentence, which is not how most people type.