I can say that having gendered nouns does add a little bit more information to communication. Like if we are talking about a man and a woman and we’re using pronouns, then “he spoke to her” is unambiguous as to who is doing what. Likewise, if all nouns have a gender, you encounter more situations where the gender adds some extra context and leads to marginally less ambiguity. So if you’re at a bakery and there are two adjacent items behind the counter, one with masculine gender and one with feminine gender, and you point and say “can I have her please”, there is no need for the baker to ask if you mean this one or that one, they know based on gender.

Not saying this makes gender “worth it”, but in an emergent system, small things like this might have given it enough of a foothold to exist.