I always use this while ice climbing and canyoneering. Great racking as people have mentioned. Girth hitch to belay loop in harness, and biner the loops together then clip them to the equip loops on your harness. In action, like stated, you can weight yourself on any loop safely, allowing short or long lengths as needed. There are various methods of using, but heed best practices - clip into anchor/bolt, webbing anchor, wrap around a thin tree and clip into itself, etc.
The only drawback to this specific item is the included biner. Lots of people would want to use the biner of their choice. But as a package, it's well worth it.