That's one plausible course of action, although being only human, I can't say with any certainly that it's the correct one.
>And what's the need for this apparent hyper optimization task the ASI is going to embark on?
Somebody's going to tell it to do so. E.g. "Find as many busy beaver Turing machines as possible." Only needs one person to make this mistake for everybody to die.
Because we're going to build it that way. There's no money in building useless AIs. The better it is at obeying orders, the more profit there's to be made. The problem is there's a point at which "good at obeying orders" becomes lethal, and there's no way to predict the cutoff in advance. But capitalism ensures you have to keep pushing or you'll be out-competed.
If you were any other animal on the planet, would you not say the same thing about what humans are doing?
What do you think life itself is?
It's a runaway gray goo scenario, just squishy and moist.