Great video, however to me the rope spacing is the main issue. I use low-stretch rope exclusively in glaciated terrian (barring an approach to a technical climb) and also train regularly with it. Even novices are able to catch a real fall, downhill, while not looking at the faller if the rope spacing is adequate for them.
That said, it's a trade off. Dynamic rope = more stretch, worse cut in to the lip, longer to haul/ascend, greater likelihood of catching a leg/crampon during the fall. Low stretch rope = less stretch, higher force to arrester, less cut in to lip, less distance in a fall.
The Denali Ranger/Guide community is a bit split on the subject. Rangers and some guide services use low-strech. Other guides use dynamic.
I also use knots in the rope, but perhaps in more specific terrain such as: steep (difficult to arrest), low-friction snow, inexperienced partner, shorter rope, skinning (i.e. ice ax not in hand) and others. Kurt's probably smarter just to use knots all the time.
Last thing - I train with real crevasse falls quite often as in the video. Personally, I tie the backup safety line to the faller, not the arrester. In many of the video clips, the arrester's ice ax is quite close to the rope coming under tension. Low likelihood event for sure, but I feel better having the backup line completely out of the way.