I am trying to understand why Azure Resource Groups, which are logical deployment buckets for applications built on Azure, are associated with a region when they are defined.
At first I thought it was to provide global distribution for disaster recovery or geographic redundancy, but then I realized that a single Resource Group can contain web apps in different regions, which can provide those features via Traffic Manager. I suppose that using separate Resource Groups would help better identify which resources are in which region, but other than for organizational purposes, I can't understand what the region definition for Resource Groups implies.
The main reason for specifying the location of a resource group is to specify a location for data/metadata for the deployment to be stored in... It also makes the API consistent (think of the paths in REST API calls) but the primary reason is storage during deployment.
The location of the resources in the group is independent/not related to the location of the group itself.