Multi-line, multi-statement closures are tremendously useful in Smalltalk.   They're the "secret sauce" that makes Don't Repeat Yourself easy to pull off. You can use them to implement your own control structures,  your own notion of transactions, etc. And all (or most) of the above esoteric hackery looks like ordinary Smalltalk.<p>People are down on I statement  Lambdas because they don't do all of the above so well.