Interesting way to retrieve a primary anchor - and (difficult to see), they do have a swivel.
But these people don't believe in modern solutions (nor in fact solutions not of their own design) and unfortunately I don't have a big enough Boomerang to fit or I'd given them one to prove my point.
I assume it's for picking up moorings. The boat only has a single roller, so most people would have to shift the anchor to use it for the mooring pendant instead. This owner thinks they've got a better idea (but who knows what it's done to the performance of the anchor!)