Difference between deleting registrant + cancelling their status

It’s unclear to me what the difference is between the DELETE registration (meeting/webinar) and update registrant status to CANCELED. It seems that regardless, users can access the “edit registration” link from their email and register again even if they were deleted or canceled.

What is the difference and when should we use either API? For context we have a page where we want to show available events and user can register or degister from our page. it’s unclear which API we should use for “deregister”