From reading the docs, it's not clear if Aurora Global Database has a lower RTO vs promoting an RDS read replica. Does anyone know if there is a difference?
AWS docs say: "For an Aurora Global Database, RTO can be in the order of minutes."
For promoting RDS read replica, RDS docs say "The promotion process takes a few minutes to complete. When you promote a read replica, replication is stopped and the read replica is rebooted. When the reboot is complete, the read replica is available as a new DB instance."
Both promoting read replica (with in the same region) and Aurora Global Databases failover takes few minutes, both have different use cases/purpose.
Global database provides regional level failover protection (Example: Failover from US to UK) compare to read replica that you referred is AZ level (which are with in 60 mile range)
Also, Global database provides low-latency local reads in different Region