Answer: The magnitude of Trump's win confirms our priors about the primary
I think a second place for Haley would effectively kill the DeSantis campaign. That's news! DeSantis pinned a lot of his hopes on doing well in the state. But more importantly, I agree with Nathaniel: Trump's big win is the headline. CNN reported last week that the White House is frustrated that many voters do not seem to acknowledge that the general election is so likely to be Trump vs. Biden. Given that, covering Iowa for what it is (effectively the last indicator we needed that Trump is overwhelmingly likely to be the nominee) could correct some of those misperceptions.
—G. Elliott Morris, 538