When biologists say "the purpose of a nose is smelling things" you don't have to personify mother naure to make sense of what they mean. Personifying the organism is often enough.

That doesn't change the fact that personification is a way to help people think about reality more easily at the expense of accurately describing it. Noses don't literally have a purpose. It's just that organisms that are good at smelling things tend to reproduce more.

The problem with Schneider and Sagan is that they confound this metaphorical meaning of the word purpose (the utility function of a personified entity) with a different meaning (ideals to live your life around). Hence their second book makes the absurd statement* that, when you strip the word "purpose" from it basically says "knowing that decreasing entropy gradients is a major reason life arose will give you ideals to live your life around." That's ridiculous.

*To be fair that statement was a cover blurb, so it's possible that it was written by the publisher, not Schneider and Sagan.