So effectively the use of a PFD in your area is more about easy recovery of the corpse than survival . . . . .
Yes, this is probably one of the main reasons to wear a pfd no matter where you are at. If nothing else, if the weather is that bad, you have drowned, the rescuers can get you and go home sooner per say etc.
Reality is, in some parts of the world, a pfd WILL NOT save your butt per say. In Alaska where the water will be as close to 32f/0C as it can be, maybe even a degree or two colder, your chance of living is probably less than 15 min! I could be wrong, but without a survival suit, I would not give you a lot of time before you are unconscious!
If the water is 60-70F temps, you probably have over an hour if you can figure out how to float that long etc.........but even still, hypothermia will set in, sooner or later you are unconscious, soon after one drowns! Colder water is sooner than warmer.
Probably best overall, is a pfd with a harness or at minimum a harness such that one can not fall overboard! I have some jacklines I put out when I know the water will be rougher, such that folks on the bow can worry about doing the bow work, and hopefully not worry about falling overboard. Clipping in many times is a good thing. Does not matter if the waves are a foot or 100' high frankly! If you feel you need to clip in, clip in! The Op's boat I believe does not have any lifelines, so clipping in in some way shape or form when the waves are in the 3-5'=+ range crossing the straights of juan de fuca, or straights of Georgia or equal around here...... might be a smart thing to do, or the CG will find a boat sailing along, no operator/person on board! not a good thing.