Or, ... you use one with a more powerful language such as the Template Toolkit
Template Toolkit is a fine piece of work, but using it has drawbacks in some contexts. Non-programmers have a difficult time coping with it*. It raises a barrier to understanding, and hence a barrier to the willingness of designers to edit templates. And the risk of mal-edits by non programmers is higher. The technique of isolating components helps.
<TMPL_VAR ESCAPE=0 stuff>
is fairly easy for a non-programmer to work around. Templates used by components are harder to deal with, but designers spend their time at the page level, at least in my experience.
The general problem is shared by JSP, ASP, and other schemes.
*Amended to say that this has been my experience. YMMV.