We use it to configure operating systems, apply security, and for day-to-day management. Our use cases include collecting information from end nodes, rather than writing shell scripts or any other types of scripts, as was done historically, and rather than even logging in manually and collecting information from the nodes. These days, you write an Ansible playbook and it does things for you. And if you don't have a playbook, you can simply gather the facts from the nodes, and that's available out-of-the-box without writing anything. You simply utilize the Ansible modules.
Our Ansible deployment is for a hybrid environment. We have on-premises services that we use Ansible to configure as well as cloud instances.