Using the account regional namespace is also described as a security best practice:
> Creating buckets in your account regional namespace is a security best practice. These bucket names can only ever be used by your account. You can create buckets in your account regional namespace to easily template general purpose bucket names across multiple AWS Regions. You can have assurance that no other account can create bucket names in your namespace. If another account attempts to create a bucket with your account regional suffix, the CreateBucket request will be rejected.
https://docs.aws.amazon.com/AmazonS3/latest/userguide/gpbuck...