Is it excellent news? Ignoring the good that will come from the money, shouldn't the fact that Musk is donating the funds increase our estimate that AI is indeed an existential threat? Imagine you have a condition that a very few people think will probably kill you, but most think is harmless. Then a really smart doctor examines you, says you should be worried, and pays for part of your treatment. Although this doctor has helped you, he has also lowered your estimate of how long you are going to live.