what's the value of "emmc.sh" in the build directory of a flasher image?

totally rewriting my summary of the BBB update process and noticed a
small oddity -- the top-level "build/" directory in a flasher image
contains the script "emmc.sh", but the systemd service that kicks off
the actual flashing explicitly executes a second version of that,
/usr/bin/emmc.sh, which starts things off by cd'ing into the build

  so is there any point in keeping a copy of emmc.sh in build/, given
that it seems it will never be executed? doesn't hurt, of course,
just unnecessary.