It is a little more than semantic search. Their value prop is curation of trusted medical sources and network effects--selling directly to doctors.

I believe frontier labs have no option but to go into verticals (because models are getting commoditized and capability overhang is real and hard to overcome at scale), however, they can only go into so many verticals.

Much of the scientific medical literature is behind paywalls. They have tapped into that datasource (whereas ChatGPT doesn't have access to that data). I suspect that were the medical journals to make a deal with OpenAI to open up the access to their articles/data etc, that open evidence would rely on the existing customers and stickiness of the product, but in that circumstance, they'd be pretty screwed.

For example, only 7% of pharmaceutical research is publicly accessible without paying. See https://pmc.ncbi.nlm.nih.gov/articles/PMC7048123/