[drcode]

Hiccup is for going html->string

This library goes from html->React data structure

The React.js system then is responsible for pushing it into the DOM, which it can often do in a way that's more performant than using a string intermediary (by computing deltas)

That's the short of it- The other part is that React is mainly a client-side technology whereas Hiccup is mainly used on the server (though these lines are blurry)