Okay. So IF there is a firm surface, and IF the mountain is uncrowded, and IF the trail is wide enough, and IF the pitch isn't too great, and IF you are choosing to do medium-to-long radius turns, then a carved turn is a more appropriate choice for a turn than a skidded turn. As the analogy I put forth before goes, this is when you've got some nails to drive... so bring out the hammer. Why? As already mentioned, it is by far the most efficient turn out of any. The friction of the edge cutting through the snow instead of scraping across it conserves more energy from turn to turn. It also more efficiently transmits the energy supplied by gravity into the direction the ski is moving. Because the skis are better utilizing gravity to supply energy, the skier's energy expenditure is relatively minimal compared to a skidded turn.
However, that doesn't make the carved turn an intrinsically better turn than a skidded turn. It just makes it the best tool for a certain job. In other situations, for other jobs, the skidded turn is going to be the tool you want.
Also, I am a huge fan of carving when the time and the place is right. Early season, firm days after a rain and freeze, late afternoons when the trails are scraped off and its too late to hit the trees, I'll be carving for sure. I just do other things as well, and don't put one above the other.