Templates are based on the XML format, which allows interesting applications. For example, they could be stored in a database and modified dynamically with xpaths.
Templates compiled in the browser
This may not be a good fit for all applications, but if you need to generate dynamically user interfaces in the browser, this is very powerful. For example, a generic form view component could generate a specific form user interface for each various models, from a XML view.
No toolchain required
This is extremely useful for some applications, if, for various reasons (security/deployment/dynamic modules/specific assets tools), it is not ok to use standard web tools based on npm.