Jack Dorsey is definitely a smart guy, I believe there is a big reason behind it. I wish he will surprise us to make it capable global communication. But my question is how long it will take to work it for a long distance?
Your blogs have very small amount solution, but the JS use cases are very large. How this little replacement can do more thing? I usually like the idea of being using as lean as possible, if it's can be possible to do more thing just with HTML and CSS that's obviously cool. Is it really possible to replace JS with HTML in near future?
BTW the toggle solution (expanding content) is good.