Not necessarily; after all, such a beacon will only let the world know that someone, somewhere is in the water; depending on where they fell in, rescue personne

Not necessarily; after all, such a beacon will only let the world know that someone, somewhere is in the water; depending on where they fell in, rescue personnel may need days to get to the site if it is sufficiently remote and the weather is bad enough. The main benefit of a PLB is to assist the vessel you fell from in finding you - unless you had the good luck to fall overboard near a heliport in decent weather or in a busy shipping lane, the PLB will (mostly) not be able to get a rescue effort by any other party under way in time.