My main use case for CentOS is technical support, fixing the network or service-related technical issues faced by the customers.
One of our products, a web server based on Nginx, uses CentOS as the base OS. When a customer calls me stating they're not able to access the web UI of a certain product or not able to access the web server, I use the terminal to see the status of the services using different Linux commands. I can also try to restart the web services from CentOS commands; that's how I usually use it.
Sometimes I use CentOS to create cron jobs when I want a server to perform certain tasks at specific times. Instead of doing it manually, I can create automatic cron jobs so a service will be executed on a certain date or time.