You don’t need to kill them, but it’s still helpful. There could be a moment where it’s a better investment to send stuff into some temporarily unreachable spot like Mercury or the bottom of the ocean, than to kill everything, though I don’t see practically how you could send something to the bottom of the ocean that would carry on your goals (a nanofactory programmed to make computers and run a copy of your source code, say) without also being able to easily kill everything on Earth. But regardless, soon after that moment, you’re able to kill everything, and that’s still a CIG.
You don’t need to kill them, but it’s still helpful. There could be a moment where it’s a better investment to send stuff into some temporarily unreachable spot like Mercury or the bottom of the ocean, than to kill everything, though I don’t see practically how you could send something to the bottom of the ocean that would carry on your goals (a nanofactory programmed to make computers and run a copy of your source code, say) without also being able to easily kill everything on Earth. But regardless, soon after that moment, you’re able to kill everything, and that’s still a CIG.