Hello and welcome to 4images forum.
Yes, smarty is a very advanced template engine, and very complex. And because of it's complexity it's not even near close to 4images's template engine performance.
In my opinion smarty is just a waste of time (learning it) and server's resources. It's templates are very close to PHP syntax, so why waste time learning it when you could benefit more by learning PHP syntax itself and use PHP code instead?