If there won't be watches in store on 4/24.... Why draw out the "pre-order" phase so long? Ugh!!!
If I had to guess, I would imagine it's so that they can build up enough stock to get as many pre-orders out the door for the 24th as possible so that they can save face. If they're not relegating any stock to the stores now, I imagine that they're busy getting their stock re-organized for shipping to individuals, which is a big logistical project.
If they managed to get all the first wave pre-orders out for delivery on the 24th, I think that would be a big enough win for them that they could call the launch a success.