I have yet to hear of any actual rope-using application that would
employ many of the sets of knots put forth here. I can assure you
that the seemingly vogue Rosendahl's "Zeppelin" bend is extraordinarily
rare bird in the wild...
I'm thinking of the daily duties where something "most useful" should
be expected to be found. ...
So what ? 
It is at times amusing that people turn to the wildness, to the popular, to the oriental, to the occult, to find something supposedly unknown, hidden, or lost, from western civilization...I hope you will not search for the most "useful" knots in the UFOs !
You have a most peculiar mis-reading : I very much looked for "most useful"
among --imagine (or just READ)-- things actually USED;
and I looked for
uses for the novel or vogue knots some are putting forth as
most useful--tellingly, devoid of the uses for them.
I have to inform you that science is put forward by arm-chair thinkers...
Ah, so now its
your turn to do the telling? Well, if you're seeing much
science in these posts there must be some kind of light (maybe not of stars)
in you eyes. I think that astrology might be more apt a likening, or religion:
all bow down to the Butterfly!
Actual applications are often performed poorly or wrongly by the "professionals".
And it takes time for people "in the wild" to learn and adapt the best solutions provided
by the arm-chair scientists and thinkers. Also, people are driven to poor or wrong solutions
because the every day hunt for effectiveness, at all costs, dictate to them to follow the fast,
easy, but dangerous path. And, please, do not use the commercial fishermen, especially
the Alaska crabbers, with their 5% mortality rate, as paradigms of professionals who do
their work as they do it, because they know better than arm chair thinkers...
This is nonsense, mostly : behaviors evolve from some rub & change wrought by
the applications --bad ones tell and are lost. That isn't a purely effective method
to betterment, but it can be simply seen (barring star-gazing blindness) that much
of what is done
in knotting by regular users works for various reasons,
and a bend such as Rosendahl's (or esp. that more symmetric like knot) has no
value. --regular use being joining ends of binding cords as bits are added to
the stuff on the needle, or of joining groundlines (if not splice-able, such as
the kernmantle conch-pot longlines are not (photos attached), for which the
fancy novel knots offer nothing desirable and are less easily made, to boot.
The gratuitous remark about fisherman safety is that, because their safety
issues come from the nature of their environment and the demands of
the industry (coupled with some loss of reason associated w/testosterone
and --alas-- use of drugs) ; they aren't injured because knots fail, and they
really do care that the 800# pots w/crabs set in the deep are retrieved.
Here, Rosendahl's knot I think would serve equally well as the Carrick,
although with its adjacent ends the latter enables a further securing by
a tape wrap, for assurance.
People are killed because of the daily hunt for profit, because of ignorance, because of bad education.
And there are also cases of rather comical arm-chair inventions going
sorely awry.
If we really wish to study the truth, we should better follow the science, not the so-called
"common wisdom", look at the libraries, not in the plastic bags and trash depositories !
Science has verifiable, repeatable experiments; it has collected observations
(field work --you need to elevate your duff out of the armchair for this) as
as fuel for building theories; it has an iterative process of trial & error, too.
Religion has all the faith in some posited glory, and
finding *facts*
to fall in line, ignoring the rest.
--dl*
====
ps : My keys cord (holds a couple rings) ends are joined with Rosendahl's
bend, nicely secured with the *mushroomed* ends at opposite sidesc qua
stoppers, for years now. (But some play cord of 3/16-4/16" (5mm) soft nylon
solid braid freed itself from the knot in a day or so.)
