He's providing these as commands to show that Vim can handle the same features as Sublime Text, but he's doing it in a non-Vim way, as far as I'm concerned.
As I said, learning the basic commands and using them. There's no need to remember a key combo for 'swap lines' because it's just 2 basic commands used in succession. I never even think of it as 'swap lines' because what I want to do is remove a line, then place it somewhere else. And that's what the commands are in Vim to make it happen.