Wikipedia’s article on grammatical gender offers some strong reasons, the main one being disambiguation of antecedents (for example, which of multiple objects in the sentence the subject or verb is referring to) and homophones (different words with the same spelling or pronunciation).

I don’t think it’s an obsession with sex per se, as much as just a legacy many thousands of years old. Some suggest it didn’t even start as a male/female thing, but perhaps animate/inanimate. It’s worth noting how many very different languages globally have grammatical gender, and that in many of them, the gender of words frequently contradict what you’d guess, as well as reverse gender in many situations. Learning languages like German and Icelandic, you’ll be warned not to think of words as gendered so much as just categorized arbitrarily, because grammatical gender and natural gender so often have nothing to do with each other.

Anyway, the rest of the article is pretty interesting too!

https://en.m.wikipedia.org/wiki/Grammatical_gender#Useful_ro...