With reference to this SO, how mature is Azure CLI 2.0, can all Azure powershell functionalities be achieved using Azure CLI?
Azure Cli 2.0 is design for ARM mode. It does not support classic mode. Azure Power Shell support ARM mode and classic mode.
can all Azure powershell functionalities be achieved using Azure CLI?
The answer for ARM mode, almost all PowerShell functionalities could be achieved using Azure CLI 2.0.