A subscription allows you to manage and control the cost of your Azure resources. Besides the financial aspect, it is also the main control point, where you can store policies that determine what resources can be provisioned and which features can be used. Managing such elements would be cumbersome without proper support in Azure. Fortunately, there are many built-in definitions that will help you to control things such as resource locations or proper security configuration.
You do not have to go to the portal to get information regarding compliant/non-compliant resources—there is a detailed guide, which describes other methods (PowerShell and RESTful APIs) and that can be exceptionally helpful when automating governance over resources. To read it, check out https://docs.microsoft.com/en-us/azure/governance/policy/how-to/get-compliance-data.
