There has long been a calculus of using more risky or long shot treatments for the more deadly or hopeless diseases. Certain types of cancer are essentially death sentences.

Maybe it's counterintuitive, but it makes a lot more sense to use ML for cancer than say a broken arm. There are so many systems interacting in cancer that affect its progression that humans really are at there limits in trying to understand them.

And as others have said, no one is letting Baymax loose in the oncology ward and firing all the doctors. This is just one more tool in a doc's tool belt -- and far from the only that will give misleading results.