CouchDB is useful for storing content like high scores into a central database from your mobile app, but you cannot use it to easily provide a nice interface for editors to manage news stories or points of interests (maybe you have a google map in your app that shows store locations). This is what we focus on, a flexible CMS for mobile apps with a nice interface for editors and not only a nice API for developers.
S3 on the other hand is useful to store files. You can also upload static JSON or XML files there, but how do your editors manage those? They cannot edit them manually and static files don't provide search capabilities from the app (e.g. only give me store locations around the user's current location).
Obviously, you could easily create your own interface for users to do things like this, but why reinvent the wheel when it is already well designed and available at a decent price?
The other market I'm seing targets users of the CMS system, i.e. the people who actually maintain the data. In most data centric projects I've been working on, you could be sure that the client will at some stage ask, how (not whether) he can change the existing data and add datasets after development has finished. This usually involved creating a CRUD user interface, which was tedious and in almost all cases, was never used.
Your front page focuses a lot on the former target group (create general datastructures, update and query them) whereas I think you might be offering more value in the latter group ("see how simple it is to add another recipe into your cooking app"). If you could combine the client's desire to control his money and time investment while making the solution easy to integrate for the developer, that might be good enough.
[1] CouchDB for iOS devices - http://news.ycombinator.com/item?id=2310863
[2] Amazon S3 for iOS: http://aws.amazon.com/sdkforios/faqs/
[3] Earlier discussion on StorageRoom: http://news.ycombinator.com/item?id=1847115