There's been numerous posts about this. They issued a press release on Thursday saying that there only way to buy one was going to be online for the immediate future. They cited wanting to make the watch as widely available as possible as the reason.
It makes sense when you think about it. Having to send pallets of Watches (which are already constrained) to sit in stores would have made getting one even more difficult. Not to mention it would of been complete chaos at the stores on the 24th. They're trying to move away from the whole "lines around the block" at the store thing.