Amazon EBS snapshots are stored incrementally and only the blocks on the device that have changed after your last snapshot are saved in the new snapshot. While this can be cost-effective for certain use cases, directly storing data in Amazon S3 using the S3 Infrequent Access (S3 Standard-IA) storage class can be more cost-effective for backup data that is accessed less frequently, due to lower storage costs and higher retrieval costs associated with infrequent access.