Disclaimer: this is purposefully obtuse.
Other effects in the game which explicitly state they kill you:
Shadows, succubi, massive damage, death saving throws, beholder death ray (notably not even their disintegration ray kills you), power word kill, vampires, mind flayers, night hags, drow inquisitors.
Clearly, if they intended for disintegration to kill you, they’d have said so. Since specific overrides general, and there is no general rule that disintegrated creatures are dead, I rest my case. QED.
I’d like to imagine that this is how non-necromantic sapient undead creatures are created, someone has all their flesh incinerated away but somehow their soul clings to the bones, and bam sapient skeleton.
In this case it could result in a poltergeist, which uses the dust to interact with things.
