I personally haven't tried this stand-up approach so I'd be interested to see what results I'd get. Bear in mind, Scott Downey is a really experienced SM, so his experience may differ from others.
As for swarming, I agree it probably wouldn't make sense for more than two to three devs to work on a single task in a story. But a story can have multiple tasks that can be split between all the devs in a typical scrum team. The key is to have the story meet the definition of done by the end of the sprint.