The ability to deploy resources using a single deployment to multiple subscriptions, resource groups, and regions provides better ability to deploy, reduce bugs in deployment, and provide advanced benefits, such as creating disaster-recovery sites and high availability.
In the next chapter, we will focus on creating modular ARM templates, an essential skill for architecture that really wants to take their ARM templates to the next level. The next chapter will show various ways to design ARM templates and create reusable and modular ARM templates.