Why is Smarty used as a template engine? [closed]

It's difficult to tell w开发者_高级运维hat is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 11 years ago.

There are many question about template engines. Smarty is most popular. I have seen comparisons here and here.

Smarty uses memory and not fast. Why is Smarty used as a template engine? I'm confused about how to choose a template engine.

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PHP is a templating engine in its own right.

The reason to use something like Smarty or Twig usually breaks down to allowing untrusted users to edit the template files, without risking php errors or mischievous behavior.

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The "best" product (the one that is the widely used) is not always the one with the best code quality, best by performance, best by memory consuming.

But the best product often is the one which has been developed earlier, which has better marketing, better documentation, better community, etc.