I reckon it depends if your employer is willing to fork out captain salaries for every cockpit crew member. Why pay two captain salaries if one captain and one F/O get the job done just as good? Mind you both crew members might be more than qualified to fly as captains and the current F/O might have been a captain in a previous life.
If the owner pays two captains, it is a good sign ; and as flexibility is concerned it is easier to plug in a F/O if required than a Captain whom does not know a thing about the principal's preferences.. ( which is the uttermost important thing in the plane, not flying it, flying it is 'granted', service is the Challenge)