Possibly a more uniform treatment of components versus "literal elements", but yeah the value proposition becomes very low.
In fact I'd argue the value proposition of JSX is already relatively low when you factor in hyperscript in regular javascript (and yes there are component-compatible hyperscript helpers for React).
I think that Hiccup's idea of writing the tree as a tree-like data structure is superior to writing a tree of function calls.
I tried doing something similar in JavaScript; the result looks a bit silly (I realized the elegance of not needing to delimit lists with a , in LISP right here) and has questionable performance: https://github.com/Lokeh/hux
In fact I'd argue the value proposition of JSX is already relatively low when you factor in hyperscript in regular javascript (and yes there are component-compatible hyperscript helpers for React).