The feature that will be useful is to be able to see the emails are triggered through D365 Marketing that the contact has received. Having that data in the timeline later when other agents (from customer service or sales for example) can see the exact email record for the specific contact they will know how to proceed (approach). For now, the only way to do this to send a "Test send" and see what the result is, but if there is a large amount of contacts this will be very time consuming and not applicable.