I know Scheme; actually implemented my own toy lisp at some point - continuations and all. Still, Racket (or Gambit...etc) is much more than the basic language, and I don't want to spend days reading - once again - how to draw a line on the screen or render a web form or use modules or do any of the stuff needed for a non-trivial application all before I get started.

I could do that if I really needed, but it wouldn't be casual programming any more. This is where all the autocomplete stuff comes in for me. I just discover the libraries I need when I need them.

As for quickfix, it means I could write the program top-down by calling function that don't exist yet, using uncreated data structures, and then with a few clicks have the IDE create all the skeleton code waiting to fill-in.

I think such tools would be valuable in any language.