RDS isn't really that great as a scaling strategy. It's only marginally easier to keep running than your own dedicated MySQL instances and it's far less flexible, particularly for disaster recovery since there is no way to do cross-region replication.
Marginally for who and it what scenarios? Features like Provisioned IOPS and Multi-AZ deployment with failover and read replicas make it quite attractive for a project without a lot of dedicated staff. So it's great strategy depending on what you want to do.