I'm obviously only speaking for myself here, but the games I ordered cover like 85% of my planned gaming-related purchases over the next year, so it makes sense for me to order them all at once for 33% off. If I had to pay the money now, there's no way I'd be able to afford it, but paying $500 over the course of a year or so for 12 newly released games really isn't too bad.
Plus, a lot of people probably ordered games that they were unsure about, since Future Shop requires zero monetary obligation from the buyer. My fifth and final order consists of 3 PS4 games, but I probably won't be buying a PS4 until mid-to-late 2014 at the absolute earliest, so there's a good chance I'll end up cancelling it.