I may not have had enough coffee yet, but I don't mean the policy part (I don't think). It's a feature thing: "sudo vi somefile" (or nano, or joe, or whatever) runs the editor as root. `sudo -e somefile` copies the file (or a list of files) to tmp (with mktemp), runs $VISUAL, and if the files have changed, copies them back.
@pid_eins
I guess there _is_ some policy stuff with it too, but it's mostly about keeping users with non-root sudo from doing bad things