I am open to be corrected on this but I believe if you choose "embedded firstname.lastname@example.org" and publish it, another user who accesses the view will need to have the saved credentials for that email@example.com account associated with their user (which is probably unlikely they will have this if its another user) as per Manage Credentials - Tableau
However if you choose "Embedded Password" it does not require the account saved credentials and will just display the view/allow user to subscribe.
So if you are catering to Viewers I would choose "Embedded Password"
Hope this helps
Thank you for your prompt response. That is an interesting thought. Though, my users are able to see and connect to the content just fine. The only change is that the subscribe button appears with the embedded password option and disappears with the embedded email option. Subscriptions used to work just fine and I have been using the embedded email option since I started which I guess I forgot to mention was 2 years ago.