Why do we have intelligence?

Paid for Claude. I didn’t paid for ChatGPT so this is the first. I’m surprised by how much better the answers are. It’s structured, detailed, well informed. It’s a lot better than GPT 3.5, slightly better than GPT 4.0 (well I haven’t done much comparison), better than any conclusion or plans I’ll write by myself. It also made me questioned: Who am I? What am I?

An organic matter that metabolise and replicate? What do I have a brain for? Obviously other things can replicate without a brain too. Are my fellow humans bothered by this question?