I believe the double pot and buried roots are all about making the plant more visually appealing to the average buyer. Also, the hole-less ceramic pot helps to protect furniture from the water that drains out of the plastic pot.
It is my understanding that most people casually buy orchids to look nice in their homes for a short while. They don't care very much if the plants die. One of the largest commercial growers in the US claims that less than 1% of people who purchase their orchids will ever get them to rebloom.
In fact, I have seen "care" tags on some store-bought orchids advising the purchaser to throw the plant away once the blooms fall! This is good business for that commercial grower, because most average orchid purchasers won't mind going back to the store and buying another plant.
Of course, it makes me want to go rescue those "disposable" orchids, so I guess I'm playing into that company's hand, as well! haha