The sample outputs look nice!

But I always hate it when a templating language grows function calls and all of that. Maybe it makes sense in this context, I'm not sure.

But if you end up using it together with another language, maybe for server side rendering or some kind of document from data generation, you quickly realize that switching between the two languages wastes a lot of time, and the templating language is never as powerful as the "real" language. So I prefer JSX, or something like Javascript's tagged template literals. Something where you use a real programming language, but where the context of the document is understood, so you don't have to worry about escaping or XSS.