I present one very simple reason why this just isn’t good enough:
A few people have said in the comments now that it will be possible to store the applications locally and run them without incurring airtime charges. In the WWDC keynote, I saw Safari bookmarks being used as the method for launching an app, but it’s possible I dozed off during the part where this local-access method was explained. Given there won’t be an SDK, I’m also curious how the UI will enable this.
If you can link up somewhere on Apple’s site that explains how this is supposed to work, leave it in the comments. Thanks!