If you're willing to agree "IQ" is in the same realm "Athleticism" in terms of realism and heritability, then I have nothing more to say. There would be no question studying IQ is incredibly valuable.

Sure, maybe there is no part of the human which is the IQ, and it's a merely a summary of other factors being expressed. I don't think IQ researchers ever claimed otherwise.

Are you familiar with "entropy"? Isn't that a statistical summary of a configuration of atoms? Wow! Emergent properties, with no physical existence are a big part of science.

What do you think "heritable" means, and why does that make it "incredibly valuable" to study?