No, it may not be harmless and could induce the law of unintended consequences and not even be advantageous to females or anyone for that matter. A literal interpretation would mean that there would be no concept of sex under federal or state law. All laws that reference sex could be invalidated and that includes a lot of things including simple record keeping like birth certificates, job qualifications on both sides, all sex-based affirmative action programs, no sex separate sports competitions for any institutions that receive state or federal funding and much more.
If I were a Supreme Court Justice, I would see at as my job to take the amendment to its logical extreme as some of them do in their position. Almost everyone could think of something they find undesirable about the potential consequences of possible Supreme Supreme Court interpretations of the ERA because Constitutional amendments are not simply feel good measures. They will have consequences as cases cases are brought to the Supreme Court based on the wording of the amendment and the ERA is very lacking in that regard.
Don’t discount that idea automatically because that is the way the U.S. Constitution is supposed to work. The 2nd amendment is another example of another very vague amendment and picked up steam over two hundred years later when it was ruled that Washington D.C. had no right to have an effective handgun ban for private citizens and future cases are waiting to overturn similar laws in other cities and states.