Difference between Cancelling and Deleting a Goal?

Summary

Need to be able to explain to employees the difference between cancel or delete a goal or remove one of those options

Content

Hi.  I'm putting together process documents and want to be able to explain why an employee would want to cancel versus delete a goal.  I know cancelling a goal leaves the goal in the goal plan and the employee has the option to copy it and deleting requires approval and removes it completely from the goal plan.  My question is why would someone choose to cancel versus delete?  Also, just to make it easier, is it possible to remove one of those options?  If so, how would I do that?