However, whenever I see a Smalltalk shell where folks are typing Smalltalk into the REPL I cringe, because Smalltalk is not really a scripting language
Whereas I see a wonderful minimal system for debugging when I've broken MVC, Morphic or sometimes both :-). My use case is to require as small a part of the image as possible to function while I work out what's happened. Any sugar on top is extra code that I might have broken!