This could be another 500 page long thread if not careful. But there is no reason that the octopus cannot be on a slip knot necklace which pops free easily and is always where it is expected to be and works just fine with a BP/wing. And there is no reason that sharing drills and switching to the octo during a safety stop cannot be done to ensure the regulator is always functional:
BP/wings will never replace jackets. Most new divers are not water people and they feel safe enscounced in their plush and padded jackets that are sold to them as safety "devices" and a lot of those jackets and back inflates or hybrids work just fine. This gentleman is very clean and streamlined and has excellent trim and was a very skilled diver. He uses a snorkel keeper which is the second best way to stow an octopus second, the best is on a necklace with a slip knot (an opinion):
BP/wings will never replace jackets. Most new divers are not water people and they feel safe enscounced in their plush and padded jackets that are sold to them as safety "devices" and a lot of those jackets and back inflates or hybrids work just fine. This gentleman is very clean and streamlined and has excellent trim and was a very skilled diver. He uses a snorkel keeper which is the second best way to stow an octopus second, the best is on a necklace with a slip knot (an opinion):