I don't know what it says now, but back in the mid-90s 3710 said that in multi piloted aircraft, Flight Surgeons could operate the aircraft in all phases of flight with an IP in the other seat. Our Quack used to fly pilot trainers with his share of takeoffs and landings.
As part of their initial FS training, they used to do primay through soloing too.
Evidently that's changed. We're only allowed to have them at the controls above something like 5k'. Not in the landing environment, for sure.
I think it's kind of stupid, but quite honestly they're not missing much and don't really seem to care. Some of them get rides in the family model F-5s from time to time, but it eats up about 3 hours of their day to get a .7. Same with bagging two seat Harrier rides when 203 is in town. Plus that has the added joy of getting added to the 2MAW authorized to fly list. That requires a pint of blood, copies of your high school and college transcripts, endorsements from your chain of command, a lock of Christ's hair, and a notarized letter from the Pope........and three weeks to process.
They'd rather spend 4 hours getting a 3.0, read a book, and eat blueberry French toast on some boondoggle.....I mean important support mission.