Nope.
I would too, and I am.
But there is a difference between knowing approximately what the other person is doing on their flow or to setup something for a checklist, and to actually be assigned a flight in that seat.
Where I work, they used to do that. The problem was not when a captain who just upgraded got assigned a seat in the right seat, or a check airman who already flew regularly would get reassigned somehow to cover an FO flight. The problem was, they'd have a reserve who upgraded two years ago and barely even flew in the left seat more than 200-300 hours a year, and had not flown in the right seat in a year or two, get in the right seat and be fumbling their way through flows and checklists, let alone getting the sight picture from the right side back and smashing the landing in pretty hard.
The union and the company discussed it and decided it would never happen again except check airman performing check airman duties.