Its got moving parts, sooner or later it will fail.

Or you will drop it over the side, or misplace it. For less money, you can get a bulletproof and multipurpose boathook, AND a backup. And you don't have to show a lubber how it works, its self-evident.

It seems to require that your mooring line already have a big eye or loop in it. I don't like those, because in a pinch, they can't be used as anything other than a mooring line, and they are hard to untie when under a strain. A simple unadorned piece of line is best, and if properly made fast to the cleat, less likely to jam or tangle under strain. If you need a loop, tie a bowline.

It might come in handy on a large boat, as the author points out, but in a large boat you have deck apes to worry about things like tying up.

Besides, this gadget won't work on the most common type of cleat.

Remember, if you haven't got one aboard, it can't break just when you need it.