Ironically, telemetry information, and it's a slim host os. At least from a corpo-tech perspective. It's nicely integrated into azures dashboards, logs and monitoring tools that kind of thing
Its for their cloud instances. Just like you wouldn't actually run Amazon Linux. If you're using their cloud platform it's absolutely the best option, but in all other scenarios you wouldn't think to touch it
I don’t think it’s comparable to Amazon Linux even, it’s more infrastructure oriented. From the Wikipedia page:
CBL-Mariner is being developed by the Linux Systems Group at Microsoft for its edge network services and as part of its cloud infrastructure.[5] The company uses it as the base Linux for containers in the Azure Stack HCI implementation of Azure Kubernetes Service