In case of emergency I think parachutes would be more safe than life-jackets.
Completely aside from how on earth 150 people would bail out of a pressurized aircraft, all expected to be able to jump into freefall in the first place, at high altitudes where they would be dead from hypoxia or exposure after a minute or two...
You wear a parachute when the risk of the "skydive" is less than the risk of staying with the airplane. This risk balance only occurs when flying military aircraft (getting shot at or single jet engines with airplanes that glide like bricks), gliders (because of the midair risk in competitive soaring) and aerobatic aircraft (because of the risk of the pilot making it come apart).
Otherwise, not worth it.