I'm not sure if I trust this foreign devilry... it doesn't look like it should work... Yeah. The first time I watched this method I was: What?!? I think you edited out a couple of steps...
Now I wouldn't want to go back...
As for the army roll. It certainly looks space efficient but it's way more effort than I'd be willing to put into folding underwear. Also I don't have enough dollar notes for all my shirts. You should follow the related video to army rolling underwear pants. It fells like I could probably fold a week's worth of underwear in that time.
I might try it though the next time I go on holidays...