In some contexts a less invasive, easier to do, or just plain cheaper test can make sense for screening even if it's not good enough to replace your other tests. So there's a middle ground between "replaces blood tests for malaria" and useless.
My pathologist friend was telling me that because machines are still very bad at figuring out if cells from a smear might be cancer but very good at figuring out if a sample has HPV fragments they've switched to letting the machines check samples for HPV and then, since cervical cancer is almost invariably caused by HPV a human looks at the smears for the HPV positive patients to search for cancer. Humans aren't great at this either, but this approach means each individual worker spends more time looking at the smears that actually might have cancer, so hopefully that lets them do a better job.
https://www.azcentral.com/story/news/local/arizona/2018/06/0...
Understand the shade you are throwing!