(see video link below)

It would be useful for a bridle, snubber or perhaps to grab the loaded side of a line to help clear an override. It should be equally effective at grabbing chain (Dyneema is the MOST chafe-resistant synthetic line, and people have been using nylon snubbers with rolling hitches for years without issue).

A longer version could also be used as a "safety" wrapped around the mast when ascending in a bosun's chair. Just loosen it to slide, and if you started to fall it would instantly tighten and grab. It would be easy enough to transfer to a second one when you need to cross spreader or rigging stay junctions.

At around $15 for two it's a pretty good deal when you consider the time it takes to splice (I have no affiliation with the Shockles company), but I have some extra Amsteel on-hand and recently developed s bit of 12-strand splicing experience, so will make my own.

One other comment -- It appears Shockles did the splices with a sewn straight bury, but the bury is shorter than it should be (it should be 72 times diameter in Dyneema). That's probably why they only rate it at 2,000 lbs while the breaking strength of 1/4" Dyneema is over 5,000. I would use the modified Brummel splice and a longer bury in my version. It will be nice to have a few of these, two sized for the mast and some shorter ones for rope.