Line by line parsers are extremely limited and markdown makes use of everyday characters we use in text for their formatting. The page itself uses style tags at the top so not sure what you mean. This is just showing off my progress so far of something I plan to use. Not an announcement telling you this is the future.
The difference isn't just replacing {} with <>. Notice that the tag name is only specified once. The end tag is only an end } not a </tag>. This is more satisfying to programmers because the SGML style allows mixups like <a><b>text</a></b>.
I'm not sure if expecting the programmer to know all HTML tags but not how they are used is the right way to go :P
Either you say "ok, i want to get rid of HTML and make it really easy to build a website" or not. This approach is neither, in my opinion.
In my opinion, that's a problem of most of those "fancy" markup languages. Why should i bother using this (or haml for that matter), if it only adds another layer of complexity and yet another "language" to learn (for me and far more important for every other person that may join a project in the future)? It may look prettier but it introduces overhead and potential other problems. Is it worth it? For me, it's not.
How does it replace markup?! It's still writing html but (more or less) using {} instead of <>. That's just silly, imo.
Markup (and restructured text) are so much more concise because you don't need to know what's <i> or <h3> or whatever.
Also, the page itself uses markup in HTML (not CSS)... wow.. back in 1995 again, are we?