As for the question you asked about the hacker not moving the funds immediately, I guess maybe he thought he has gotten full access to the account and felt he should keep it for now and withdraw the money later, since prices are going up? I’m just guessing though, but it’s good that you got your money out before stories that touch.
It won’t be because of the price are going up because if they just withdrawal the coins to their account without converting them to fiats.