At least here (not US) when you take a course for skipper license you also have to show ability to swim, put on lifejacket while in water, tie bowline around yo

At least here (not US) when you take a course for skipper license you also have to show ability to swim, put on lifejacket while in water, tie bowline around your waist and couple other. The tasks are not particularly hard but this is done in perfect conditions and assuming a person that has actually trained for it. People land in water in all sorts of situations including getting heart attack or knocked unconscious by a blow to the head. People who can't swim or get shocked by cold water may simply not have ability to think clearly at all even if they are perfectly fine otherwise. A PFD that is not worn, can't activate automatically is as good as ballast in those situation. I would also add that PFD has to be able to turn your face into the air unless you are in a situation where there is a minimal chance you get rendered unconscious and you can get immediate help.