Quoting from the RDS site, this is how Amazon is presenting the value prop:
Amazon RDS automatically patches the database software and backs up your database, storing the backups for a user-defined retention period. You also benefit from the flexibility of being able to scale the compute resources or storage capacity associated with your relational database instance via a single API call. As with all Amazon Web Services, there are no up-front investments required, and you pay only for the resources you use.
More AWS info at
and elsewhere at
Overall, this is a good move from Amazon,
and the whole space is going to continue to change
rapidly in the near future,
see for example