It is not supported by default in browsers

Writing HTML is often simpler and easier to remember than the markdown equivalent.

It is indirect. Sometimes you don’t really know what you are going to get, depending on the complier, whereas with HTML you can be hyper specific. This is also why I dislike SCSS.

It's a design decision that deserves more consideration. What should the syntax for this particular piece of software look like?

I've been thinking about this more as I add light formatting to Special Fish.