I'm so confused as to what they're doing with this. Why create a pre-order when digital is the only option you're offering? The majority of people will end up downloading it for free from zippyshare anyways, I personally think creating a pre-order option with (for now) no vinyl, cd, or bundle options is kindof pointless.
They offer pre-order so they can attempt to make chunks of money in advance. Also, possibly to get people who would normally just download it for free to consider paying for it now while they still have a chance to make money before it's online for the masses.