Cloning Test Cases in JIRA is very helpful for test analysts as it saves lot of time in rewriting the similar steps for closely related scenarios.
You can easily clone the existing test case and then update the test steps and details as per the new scenario.
By doing cloning you do not have to redo all the work with test case properties and steps which are common across all the test cases of that functionality.
In this video I have explained how you can clone the Zephyr test cases in JIRA.