Performance, primarily. Hiccup that is generated _at runtime_ is incredibly wasteful; you allocate a bunch of immutable vectors and maps, then parse them into R

Performance, primarily. Hiccup that is generated _at runtime_ is incredibly wasteful; you allocate a bunch of immutable vectors and maps, then parse them into React elements and throw them away, every time your component is rendered. This is a constant performance tax on your application and makes Reacts tradeoffs re: virtual DOM worse. React Elements are already data (they are POJOs), so you lose nothing in terms of declarative-ness using hiccup vs. functions/macros. If you're very attracted to hiccup syntax, you can still use hx's hiccup parser with helix (docs incoming) or try out a library I wrote called thump[0], which uses reader tags to parse the hiccup at compile time into React Elements. 0: https://github.com/Lokeh/thump/ https://github.com/Lokeh/thump/