Something to be borne in mind is that American fish are dumb!

Many things that catch bucket loads of fish in the USA don't work so well over here. I don't know about these yo-yo reels, I bought one many years ago in the US and, not knowing any better, being only a kid, tried it on the local canal. All I suceeded in doing was feeding the fish when they stole the bait right off the hook without triggering the device. After a couple of trials I gave it up as a bad job.
Given that in a US lake my worms would have caught bass, crappie, bluegill or catfish, all good eating, whereas over here the choice is rather more limited, even if you assume that you ARE going to be poaching. Mmmmm tench...

. Since the device is meant to be tied to an overhanging limb and the length of line is limited, I don't see it as an effective method for fishing in the sea, unless you have a pier handy.
The size and weight hardly make it something you would pack for "survival" use.
Sooo. How exactly are folk going to use these?