It would be very useful to be able to see the number of outgoing emails generated from XF instance. This would help people to decide when choosing from various SMTP providers. Also, if the types of emails are also counted separately, admins can better tweak configurations to optimize performance. Recipient email domains might also be a useful stat. If the number of emails are significant, one might also want to enable Email Actions. Currently, this information is only available at the SMTP relay service (or by analyzing logs, if running a local relay server).