I would have to disagree on it being a minimal difference. People don't usually feel comfortable spending $100+ on an item they aren't going to be immediately receiving. That could have been $100 spent on something else that month. You may not have that money right at that moment, but know you will a few weeks from now but then the item might be sold out by that time.
The comfort of pre-ordering without being charged is what people prefer because they aren't going to be financially burdened by such a huge purchase. They have time to save money (if they need to), time to mull over the order without losing the chance to reserve the item, and there is no fear of being pushed into an impulse purchase due to the limited nature of the item.
I see what you mean, though.
You're right. I suppose the difference here is that it's a limited item, since you can still pre-order the regular game. It's a little sucky that they announced it so late, for those who do need to save up for it.