It's a hypothetical example to show that there might be kids who are inherently good at different things, and that focusing on intelligence as the attribute not to praise hasn't played out over the last 18 years the way people seemed to expect in 1998.

My point is that intellectual aspirations are just as valid as athletic ones, and that kids should be free to choose their goals and dreams with full awareness of their own advantages and disadvantages.

What's the benefit of praising a child for their intelligence if intelligence is immutable?

The benefit I am proposing is that truly intelligent children won't be afraid to use their intelligence to get ahead, nor be afraid to admit where they might not be ahead. IMO maximizing individual potential puts society in a better position to maximize societal potential than trying to normalize everyone to be similar.

I think you're saying that unless you give intelligent children permission to use their intelligence, they won't do so, or will do so less. I find that very dubious. What evidence do you have for this? I even feel (though I hope I am mistaken) that what you are really after is a hint that it's okay for your kids to feel superior or entitled in some sense relative to kids that are less intelligent. If intelligence is useful for producing work, why not let all kids be judged by the work they produce, rather than something abstract like intelligence?