What are they?
Optin status tags are an easy way to reference a group of contacts with a certain optin status. These tags are set automatically upon installation, but you can change them if need be. For example, changing them to your language.
How to should I use them?
These tags are applied to contact automatically whenever their optin status changes You should NEVER apply them in the funnel builder using the apply tag step.
Instead, you should use them when you want to reference a particular optin status. Like when you want to send a broadcast email to your Confirmed contacts.