Keep in mind that `git am` is not identical to pulling the commits. You might be applying the commits on a different base, and certainly your committer field will be different (not to mention any substantive changes you make). As a result, the sha1 of the commits you create will be different than those of the original submitter.

This makes life harder for the submitter, because they cannot ask a simple question: were my commits merged into the upstream repository? Because no, they weren't; but commits that are the moral equivalent were. Usually `git log --cherry-pick` can correlate the two, but not always.

We do use `git am` upstream when working on git itself, for the reasons you indicate in the article (plus we like mailing-list based review). But it does come at a cost in managing the various versions of patches.