Email templates don't have smarty tags. There are only placeholders that will be replaced with *static* content. This means that there can be no loops, no if/else, or other control blocks in the email templates. Which sucks.
Replacement content is defined by php code. Usually it is retrieved from existing data (order reference code, customer name, etc...). In some special cases (like here), the content is generated by evaluating smarty template. Template returns static html markup, which is then replaced into the email template.