Setting up the application in multiple AWS Regions ensures that in the case of a regional failure, the application can still remain operational, as different Regions are isolated from one another and do not share single points of failure. This design provides high availability and disaster recovery capabilities. Using Availability Zones only would not protect against a regional outage. Edge locations are used primarily for content delivery and caching and do not support application deployment. AWS Local Zones are an extension of an AWS Region to provide low-latency access to end-users but are not suitable for full-fledged regional disaster recovery on their own.