My motivation for currying macros came from the recent "afn with" discussion. I had a w/afn macro which looked like a manually-curried function, so I figured it wouldn't hurt to add it to the curry fn:
(mac w/afn args
`(w/rfn self ,@args))
vs.
(= w/afn (>_ w/rfn 'self))
Your [] syntax definitely looks useful, but I use (fn ((x y))) more than (fn (x y)).