RDS is very useful for companies which are big enough to employ, say, 2 programmers, but still too small to employ a DBA.

The hard part of running a database, in my experience, isn't setting up or running it. The hard part isn't even configuring backups.

The hard part is noticing that your backups have been broken for years, before you actually need to restore from them. Yes, yes, you know how to do this correctly. But you delegated it to the sysadmin, the sysadmin subtly broke the backup scripts, the scripts have been silently doing nothing for 18 months, and then the sysadmin got a new job.

This is the main value proposition of RDS: Your data will be backed up, your backups will be restorable, and most of your normal admin tasks can be performed by pushing a button.