What is the advantage of breaking up a large change into multiple small PRs, compared to multiple small independently-reviewable commits as part of a single PR?

What is the advantage of breaking up a large change into multiple small PRs, compared to multiple small independently-reviewable commits as part of a single PR? If a PR introduces a new function that will be used in the next commit, I would much rather see that next commit using git, than hunt for it in the PR queue.