I'm not using it in that way.
I have a forum that I send email to. Some of these accounts are 20 years old. They are mostly work email, and some of these people have moved on.
When I send the email, some bounce.
I want to make sure they don't have a newsletter account too.
I found this method much easier than searching for the user.
I know it sounds silly and only takes a few more seconds to search, but when you are looking up over a thousand accounts, those few seconds help.
I then want to make sure I marked them as confirmed.