It depends on your requirement. According to the Rundeck community, we can use Rundeck and Ansible together. Rundeck gives a great GUI front-end experience and ties with the Ansible automation alongside different tools used by other groups. Rundeck's powerful access control capabilities can be used to safely provide other users and teams with self-service access to run Ansible playbooks.
So, according to my knowledge, if you love to work with the CLI, then you can use only Ansible. But, if you want a GUI, then you can go with Rundeck and Ansible together.
To know more about Rundeck, you can go through the official link given below.