but would there be hunger at all if eating did not serve a purpose?
Same with sex. “Hornyness” is a desire for something you need. Without that desire, the human race would never have been.
And man has the ability, with both, to bring to the table more than just the raw performance of the task to keep himself and the species functioning.
I will add this: With man, sex brings an emotional element that does not exist with animals. Another thing: Human females are not like other mammals. They do not become desirous of a sexual partner only when “in heat”.
The human body we occupy is extremely complex, both physically and physiologically. It is why we have fancy kitchenware stores and sex-toy stores. And both needs, when unmet, bring unpleasant results.
When a person with a sexual appetite does not get that appetite fulfilled, there are very negative circumstances to that person and they may expand to his/her relationship with others. This is one reason women used to let their husband “have his way” with them even though they were “never” in the mood. The bible is pretty clear about who’s body a spouses is. Our generation forgot that.
It is why there are a LOT of frustrated married men in this country. In a previous marriage I was one of them. That person set me free after 20 years and I’ve been married to the woman of by dreams for 15 years now. We are completely sexually compatible. And my live outside the bedroom changed markedly. I’ve gone from being a total whimp (”whipped” would be the more accurate term) to being pretty much the alpha dog wherever I go. Who knew?!
Nonetheless, sex is about babies, for all creatures, regardless of any other benefits or liabilities.