Bagpuss
Legend
is there really much difference between:
1. I hit you for 10 damage, ongoing 5.
2. Other people act, maybe.
3. You start your turn, take 5 damage, die.
vs
1. I hit you for 10 damage, ongoing 5. The 5 happens right now too, you die.
Either way, you never get your next turn.
There is a huge amount of difference between those two when you consider the number of powers leaders have that grant saves. The Cleric even has an at-will one.