So you can build a globally distributed, redundant, eventually consistent object store with high availability easily and conveniently and without allocating developer time that could be better used building..oh I don't know, the actual business logic? Not to mention ongoing maintenance and its expense.
It's ridiculous to suggest that the entirety of the AWS offering is something that is just slightly more convenient than what could be built in house.
The ease through which Amazon provides the ability to architect incredibly globally redundant applications is unmatched. But your business probably can’t afford to implement at that scale, Amazon or otherwise (geographically load balanced DNS, multiple primary databases across regions and their associated followers, replicating S3 objects from all primary region buckets to secondary regions, instances for each application running multi-AZ in multiple regions, etc).
https://docs.aws.amazon.com/AmazonS3/latest/dev/crr.html
> Cross-region replication is a bucket-level configuration that enables automatic, asynchronous copying of objects across buckets in different AWS Regions. We refer to these buckets as source bucket and destination bucket. These buckets can be owned by different AWS accounts.