Likely one doctor per location, with a bunch of PAs doing the work.

They still use your insurance. The service makes it extremely easy to get lab work done and see a PCP very quick (I set up appts same or next day). I've used it for physicals/checkups and for getting set up with physical therapy. My local hospital system had a multi-month long wait to see anyone for a simple annual physical.

tl;dr - quick and easy access to a consistent PCP

A good app where you can schedule appointments sometimes within the same day or often a day or two, a dedication to on-time appointments in the office (I've yet to wait for than a minute or two beyond my appointment time in 5+ years of membership, across different providers), and fast turnaround of lab tests that they run often in-house.

I couldn't possibly go back to the old way of waiting weeks for an appointment and waiting god knows how long once I get there.

EDIT: A have a handful of doctors to choose from here in Seattle that rotate between the offices in the city, along with a bunch of nurse practitioners