Azure App Configuration provides a great set of options for the people who would like to store the configuration on cloud and manage through a central location. On the other hand, Azure Key Vault is a service that lets you manage all your Secrets, Keys and Certificates. There is a hint of both being connected, but for the time being they are working as two separate services. Connecting them would be great as it will help storing secured app configurations.
This article focus on how the each service is available as of now.
Think of an application that is hosted on Azure and distributed across multiple regions. If it is a large scale application, you may have divided different worker roles across the regions. Eg: An App Service along with a Database separate for the East US. Then another for Australia, while the load balancer and metadata information are geo replicated.