It does, it's a great point to make against the heteronormative "homosexuality is against nature" idea.
The reason why it came about is because, especially in humans (as Desmond Morris says, we are literally "sex machines" compared to most species and most primates--we mate even when females aren't fertile, and we do it in a variety of situations and settings that have nothing to do with reproduction), sexuality serves psychological, social and other functions that far exceed and act as a counterweight against the mere drive to reproduce or the evolutionary advantages of producing young. The development of secondary sex characteristics such as breasts and large penises (the average human penis is far far far larger than any other primates, and well beyond the size it "needs" to be), and some biologists would even say hairless skin, has been central to human evolutionary development. Our young need more touch and more direct supervision and psychological nurturing than just about any other species.
We are basically the "sex" animal or the "love" animal.