Its great that we can see the history of emails that are related to a reservations.
It would ALSO be good to see the history of emails related to an email template or Trigger. This is useful when we need to change or update a template and may need to see who received it BEFORE we changed it so we can send an update to them. At the moment, that requires going through each reservation -- or does it?
Take a look at "Tools" then "Email History". Use the "Filter" tab at the upper, left to narrow your results.