A simple one can be there for extra cordage. Say a monkey chain which will come apart in seconds. I put those on all kinds of things like zipper pulls. A more complex braid, especially in leather with turkshead knots around it, maybe to much trouble or nearly impossible to take apart and turn into cordage once its set for a while. I love braiding leather, but though they look very nice I cant see the point of putting one on a working knife.