were a big deal in the past when sails and line
stretched like crazy and winches
were not invented. They have made a comeback at various times both for racing boats and for cruising boats.
For racing boats self tacking jibs
were typically used on one design boats where absolute performance was not as critical and the rig
is set up so that there is enough sail area in the mainsail and small self tacking jib
(typically somewhere down around 90-95%) to deal with the range of winds (SA/D somewhere up in the 20''s) that they are likely to be raced in. In any event the fad comes and goes. At the moment it is gone because the sail of choice seems to be ''lappers'' (somewhere around 110%) which are so easy to tack that self tacking jibs are not worth the loss of performance to a racer (or to me as a cruiser).
Cruising boats and daysailors are more complicated in this regard. There is something nice about short tacking by simply throwing over the helm. (If I need to short tack and I am alone and not in a hurry, I will sometimes short tack under mainsail only which works well on fractional rigs
but that''s another topic) In that regard a self tacking jib really makes sense.
What makes that less than perfect is that Cruising boats and daysailors are often set up with a small enough standing rig
(mainsail and jib) that the boat won''t scare the ''Bjeez'' out of you everytime a big gust hits you. (There is a logic to that concept that even a performance oriented sailor like myself can understand.) The trade off to that is that you need to either motor or carry a fairly big genoa if you are going to get anywhere in light air. When you add in the serious loss of performance that comes with the reduced sail area and inability to fine tune the sails shape, if you care at all about performance a self-tacking jib is a really hard pill to swallow, especially when lappers are so eay to tack and offer a major jump in performance.