[R] Why do some research papers not mention accuracy as a metric?

Hi, I am working on foundation models within the space of opthamology and eye diseases. I was reading a paper and to my surprise, the researchers did not list their accuracy scores once throughout the paper, rather mainly the AUC and PRC. I get that accuracy is not a good metric to go off of solely , but why would they not include it?

Here is the paper for reference: https://arxiv.org/pdf/2408.05618