Anakin understood that what happened in his Dreams didn't have to correlate to the waking world. But people woke up with replaced arms, wounds, or new bodies all the time. And the way Ahsoka talked about the Sith, they seem like an entity all their own irrespective of the person they’d once been.
He considered the power dampeners idea.
"I'd be in a prison?" Trapped with his hate and misery. Powerless to harm others, sure. But what was the point of a life stuck in captivity?
"If I fall, I'd rather die than live trapped with nothing but my own hatred for company."