You can review how the message will appear to the customer (with the added Traits populated) before saving or adding to a playbook [Below].
Click on the Test Tab at the top of the page.
In the Search for a test Contact field, key in the name of an existing contact
Under Click on a Contact to Display and send Test, the contacts name, or a selection of names, will appear. Click on a name and the populated message will appear to the right.
Review the message and edit as required. Oh, don't forget to hit SAVE!