[TazeTSchnitzel]

Unlike HTML, the the syntax is minimal and trivial to parse (there's no attributes or implicitly-closed tags, and there's only a single character entity (<<)), and it's limited to a very small set of clearly-defined formatting options.

In lacking most of HTML's complexity and features, it lacks its security issues, too. And in being very small, you can reasonably expect the whole spec to be implemented.

But yes, with a very strictly validated, very small HTML subset you could get a similar effect. At that point, though, why use HTML?