All crew members need to gain experience in any position, the galley position in club is proving rather unpopular and ideally experience does count.
However there is an element of letting crew get experience doing the galley in club
I thought the "Thrown in the deep end","Sink or Swim" method of training had been discredited years ago!
Someone who has recently been first trained, I would not deny them a chance of gaining experience even if the service took a little longer.
If we are to believe CFC/Fume, we are talking about a cabin service falling apart not one that "takes a little longer" (or I'd agree with you).
Everyone has to learn sometime. But watching a more experienced person doing the job first would be far more effective training.
I wouldn't let a low-hours-on-type FO do a night landing, on-limits crosswind, curved approach into JFK - even if in theory he's capable of it.
I'd let him watch me get it wrong, first....