Why would anyone use this class in comparison to Smarty, for ...

Why would anyone use this class in comparison to Smarty, for example? It tries to be a simple version of it, but ends up being slower because it has to parse the same file multiple times; Smarty does it once and compiles a PHP file, which makes subsequent loading much faster. So this being called "lightweight" is a misnomer; it's only lightweight in the sense that the source code is minimal, not that it actually performs better. Further, it only works as a separation between business logic and presentation logic for the simplest web sites. For anything requiring HTML to be repeated or conditionally displayed, it falls apart completely by forcing the creation of multiple TPL files and convoluted PHP code to make it all work. Last, even if Smarty is considered overkill initially, a developer may utilize more of its features in the future. This "system" provides a dead-end.