Ever here that saying, "sometimes you have to lose money to make money"? No, I'm no talking about the saying, "you have to spend money to make money", this is very different. But losing money to make money can greatly apply here. I'm not saying either that Blizzard's goal was to lose money, but either way, they knew it would be a win all around regardless if their movie was a smash hit or not.
Really hard to explain without writing a book. I wasn't going to reply but since you linked that little bit about ROI, I thought you might understand how that can't really apply to Blizzard atm.