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.
RAW, a pile of dust is not a playable character option. Sorry.
RAW, you also cannot play as a dragon fairy princess. That would be homebrew.
You REALLY want to play a pile of dust…? Well, okay, we can homebrew that for you.
Well I didn’t start as a pile of dust. I became one via a RAW spell.
Pfft, you could play a dragon fairy princess in 3e. Probably at something like a +10 level adjustment.