This is because on July 31st, Kingdom Hearts 3D: Dream Drop Distance is to be released in the US. By then, it will have already been out in the UK for a week - as it will be launched on July 20th over there, which is not usual.
An insightful glance at some of the features in the game will be provided upon watching a new trailer as well. It features much information including exploration, combat and boss battle. Hardcore fans can also get the demo from eShop at no cost.