If you have an existing rule, you can Copy it. However, when you click Copy, the subsequent screen is confusing:

• The page does not have a "save" button. It only has a "Turn on rule" button, despite the rule not actually existing yet. If you navigate away from the page, the rule is never created. Thus the page implies the rule has already been copied when nothing has actually been created yet.
• The page forces you to enable the rule in order to successfully complete the Copy. There can be scenarios where a user wants to copy a rule but not enable it. For example, if they want to duplicate a rule for revision control purposes.
• To a certain extent, the presence of the pre-populated name of the new rule "Copy of [rule name]" up the top left of the page gives a slight impression that the copy has already been completed and that this is the name of the new rule. But the rule hasn't been saved yet. This may be also related to the presence of the "Turn on rule" button.