Div sac can stop a wipe, has stopped wipes and will continue to do so. If you look at a lot of twins strats they involve using div sac + aura mastery to stop a huge (and it is huge) amount of damage. It can make the unhealable, healable and the healable, trivial. At the start of our hard mode attempts, we found the XT's tantrum was causing problems. We had 4 paladins in the raid and we started to experiment with div sac and we've never loked back. It insane, probs boardering on overpowered and mitigates a huge amount of damage.
Just in case you didn't know, when you bubble, it continues far past the limit of divine sacrifice, ie you don't stop 100 and whatever % of your hp, you in theory stop and infinite amount of damage. Also your example doesn't do that much justice to div sac as at the start Koralon's aoe doesn't tend to kill the raid, but a bile in the melee or if too many people are grouped up at range can be saved by a quick div sac/bubble.
Honestly I cannot recommend intelligent use of this ability enough. Try it on XT during tantrum and just watch how insanely easy it becomes.