Do we know that that’s how the circular numbers are used? They don’t say. Personally I’d dislike that in my numbered lists, but I’m sure others would like it.

> checkboxes

Again, I doubt those checkmarks are clearer than an x. But again, I can see how some people would prefer those. That’s not nothing new to this font, though.

> and bullet points

Where are the bullet points in that example? I don’t see a bullet symbol.

> having ligatures

Ligatures are useful for none of those examples. And it’s not even clear if that’s how they work, since they specifically and exclusively mention ligatures for arrows, not the other symbols. Furthermore, they specifically mention (emphasis mine) “improving support for Markdown and ligatures” meaning those are separate features.

> that look better w/ those are not crazy.

Who called it crazy? Please don’t straw man, I’m not arguing there’s something wrong with adding those features, I’m asking how they relate to writing markdown. Which they mention but haven’t explained. How, specifically, is writing markdown improved by using this font?