DevOps is primarily all about people and process, so just focusing on some examples of playbooks or roles in isolation against a switch or firewall wouldn't help network engineer deal with the real-world networking challenges that they encounter every day. Selecting the correct tooling to facilitate processes is also important after the actual goals of a project have been established. Tooling should be selected after the business requirements have been made clear and not the opposite way round.
A network engineer could easily type in those commands into a network operating system as they could type commands into an Ansible playbook, so it is important to look at where the use of a configuration management tool such as Ansible adds real business value.
Implementing a new tool in isolation doesn't really help the network teams improve efficiency as a standalone activity, but the modules that have been created in Ansible to manage Arista...