Explanation:
Box 1: User subscription and low-priority virtual machines
Azure Batch offers low-priority virtual machines (VMs) to reduce the cost of Batch workloads. Low-priority VMs make new types of Batch workloads possible by enabling a large amount of compute power to be used for a very low cost.
Some examples of batch processing use cases well suited to use low-priority VMs are:
Development and testing: In particular, if large-scale solutions are being developed, significant savings can be realized. All types of testing can benefit, but large-scale load testing and regression testing are great uses.
Supplementing on-demand capacity.
Flexible job execution time.
Box 2: Batch service and dedicate virtual machines
Reference:
https://docs.microsoft.com/en-us/azure/batch/batch-low-pri-vms