Separating the application itself from the database is an interesting idea. But then you would still need to host a database yourself somewhere. If you don't trust me you must also be afraid of me messing up your own database with my solution (My solution would need write access).

A lot of mobile application developers are probably not experts in server management and backups. It is not their priority and core competence. They want to build great applications quickly.

My solution gives them an easy to use CMS with a REST API for a low monthly cost, and they don't have to care about backing up data themselves. If they don't fully trust me, they can export their data from the CMS regularly themselves, so in a worst case scenario they still have their content.