In a nutshell CommVault as a Data Management platform, provides an end-to-end eco-system with different feature sets to manage on-prem and Cloud based Backup (allowing a single pane of management).
On top of the above, there are various reason based on different organizational requirement that leads to end-users wanting to move to using AWS S3 as a Storage Target, this might include:
- Better utilization of Deduplication
- Flexibility in mixed-deployment (on-prem and Cloud)
- Orchestration, allow testing of pre-production environment in DR Test environment prior to moving to Production (live-sync)
- Long-term repository of Archive Data, without saturating on-prem resources
- and etc
Generally it is down to the organizations needs and requirement, which dictate the use of AWS S3 as a Cloud Library. If CommVault is already deployed in the environment it would be a natural choice to also utilize CommVault to manage the end-to-end backup infrastructure allowing overall ease of management.
Hopefully that helps