3D Land is an example, it isn't the point. The point is this:
When you fill up the SD card Nintendo provided you will be buying your own storage but you will still be paying full retail price for the game.
Now ask yourself, how much is Nintendo saving by not having make a card, box and insert? How much are they saving not having to distribute it to retailers or give retailers a cut? They can't even offer you a $5 discount!?
Add to that, they are selling copies that will never end up in used game stores, that just means fewer used copies out in the wild. I am sure that has some monetary value?
All that aside, I would still be tolerant if they allowed game sharing and had an account system like every other DD service.