This is a neat syntax, but it doesn’t seem at all typesafe (typesafety was the main benefit of JSX over the various string templates that came before it).
It's completely possible to write a type-checker for HTML templates like lit-html. In TypeScript we even have access to third-party extensible interfaces for all the elements with the HTMLElementTagNameMap, so we can check buildings to properties.
We'll be working on a lit-html type-checker for TypeScript early next year.