The scenario where this is helpful:

Descending semi-technical terrain, and you come to a steep section less than 25-35 feet, where there is no fixed anchor, half the rope is in your pack, and you need to lower the first person, and you want to rappel down second because it's too dangerous to down climb, and you desire to not leave any gear behind. And you find a conveniently located terrain feature (rock horn, rock pinch, tree) to wrap the rope around that won't get hung up when it pulls....pretty specific, right?!

When guiding, this can be the case while short-roping a client down 4th class terrain. Then you come up to a small section of 5th class terrain (real climbing) you need to descend:

1. Belay the client down first from a seated belay or some other anchor position.
2. Give enough slack to client so they can sit down, making sure to not tension their rope.
3. Wrap a bight of rope around the anchor feature.
4. Pass 5-7 hitches through, alternating rope sides. Essentially, you're creating a daisy chain, only with two ropes instead of one.
5. Rappel the non-client end of the rope. Making sure the client end stay loose.
6. Once down, pull the client end of the rope first. This breaks the first daisy loop.
7. Alternate pulling on each rope individually, back and forth, until the final hitch releases, and the rope comes down.
8. High five that the rope did not get snagged, re-coil, continue the descent.