Hey Kai Akua:
Good post on showing those pig tail open end connector swivels. I used to use them for trolling quite a bit but that was with single strand wire leader with haywire twists. But I do not remember them being any more pricey than the snap swivel ball-bearing variety, maybe a few cents. I will compare prices next time I see them again. Lately, I have fallen away from using them, perhaps because I do not see them everywhere. But another reason was that I just got tired of looping the leader around a few times to get it all the way on. I simply reverted back to the snap swivel, ball bearing of course. To date, I have never had a failure with the snap coming undone, deforming, or the ball-bearing falling apart. So I cannot say, yet, that they are deficient in any way. I guess I will have to experience a hard knock at some point in life. In the meantime, the snap is the most convenient item for me to use.
And yes, the melted ball on the monofiliment provides one more step of security before crimp slippage can occur. But I do not do this anymore either for swordfishing, since I am recently practicing the Tag-end squid rigging approach as Adm. Mike described it. For this I like to have a sharp angled cut on my loose tag end. But to make up for a mono bubble on the end, one can simply use the aluminum crimps. They are long enough to permit two crimps, where-ever they are used. But I have never had a failure on a single crimp either. I just make sure I squeeze that crimper tool on the crimp (figure 8s only), positioned longways, until the crimper stops hard against itself. Using a good crimper.
All of my failures have always been from the main mono breaking or a hook relaxing its shape (well once from a regular swivel failure) and I guess I have never gotten to the next point of failure, like resisting a marlin with 200+ lbs. of force. RT