I thought the primary importance of machine vision for this kind of cancer screening was that it doesn't give so many false negatives due to fatigue? IIRC there was a study that went back over cancer patients' screening tests and found that most of them had failed to identify visible, diagnosable tumors well before their disease was actually identified.
A very important use case is that a lot of places don't have easy access to good diagnosticians, and software + hardware are easy to scale while humans, not so much.
