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.
Well I didn’t start as a pile of dust. I became one via a RAW spell.
So? That doesn’t make it a playable option. Point to where it says, RAW, that you can continue to play as something you’re turned into?
RAW, it is not a playable character option. Sounds to me like you prefer to abide by RAI…
I don’t need to point to where RAW says that I cannot play it because nothing leads one to believe that you can’t. If your character is polymorphed, its state changes but you can still play it.
Where does it say that, RAW? I’m using your own logic against you. You’ll have to come up with a better response than that.
Edit: to clarify, where does it say RAW that you get to continue playing when polymorphed into a non-playable character?
You could say that about anything. You want to move left? Point to where it says, RAW, that you can move left.
You can do anything unless the rules forbid it. And there’s nothing forbidding continuing to play after your character is transformed any more than there is anything forbidding you to play while they’re wearing a red shirt.
You being able to move left is covered clearly by the rules under movement speed.
You cannot “do anything unless the rules forbid it”. That’s not how RAW works.