I am looking for some feedback on this question, not necessarily a solution.
We use Intronis cloud backups for our environment. Intronis offers Exchange 2013 item level backups which we would like to implement. To implement them though we would need to take the distinguished username of all users in AD and set them up to be an email address in Exchange. This would look something like firstname.lastname@example.org. Personally, I think it's an awful setup but I will also say that I don't know of the consequences of setting up these new email addresses. Our users have legitimate email addresses that would be set as their default address, the new distinguished email address would be a secondary address and would never be used to send email, only to be used for the Intronis backups.
I am looking for feedback from different IT folks about this, your thoughts, and any potential pitfalls you think we might encounter by doing this.