This has been going on for several years. Dead Space 3 comes to mind and I'm sure there were a few before that.
For collector's with a backlog or who aren't sold on the game, it makes a lot of sense. You can get the extras now and buy the game at a discount when it's discounted later. Most people justify the price of a CE/LE by factoring in a $59.99 game and let's face it, games decrease in value very very quickly