A use case for this would be for internal customer feedback. After you enroll and attend an event, it would be nice to auto send an email to that person. The email could contain a link that would auto launch PowerApps and the app that was created for feedback within PowerApps. It would also retain the key from the email so that would be tied to the response or be used to bring up the employee info.
You may embed a PowerApp link on a web page, and/or send a link to a PowerApp via email, by using the unique URL shown in the details section of the PowerApp. However, anyone clicking on the link will need access to the app and its' dependencies, such as data connections within the app as usual.