Ansible's idempotence makes it a great target to use in CI/CD pipelines. After all, there's no risk in running the same Ansible playbook multiple times even if nothing changes between the two runs. If you use Ansible for your deployment code, creating a CD is just a matter of preparing appropriate acceptance tests (such as smoke tests or end-to-end tests).
The declarative approach may require changing the way you think about deployments, but the gains are well worth it. Besides running playbooks, you can also use Ansible to perform one-off commands on remote machines, but we won't cover this use case as it doesn't really help with deployments.
Everything you can do with a shell you can do with Ansible's shell module. That's because, in the playbooks, you write tasks specifying which modules they use and their respective parameters. One such module is the aforementioned shell module, which...
