The Share Link is for sharing the video or collection on social media or if you just want to give someone quick access to it without the need to create an account.
The Digital Delivery sends the recipient a unique url (different from the share URL) which allows them to take possession of the video or collection in their own free account. They will then always have access to it even if you close your account. This is required to view content through our apps. If the recipient only has the share link, they will only be able to view the project in a browser.