That was my reaction, too. Out of curiosity, I searched the beginner's installation guide (https://wiki.archlinux.org/index.php/Beginners%27_guide) for dd, and there's no mention of it. The man page for dd was more informative. It's a standard convert and copy tool that I've never used despite pretty much living in a terminal for the past two years. I still think arch might be for me.