To me it's because they provide a simple way to solve the hygiene problem in an interpreter. That is, it's easier to implement first-class macros (which allow

To me it's because they provide a simple way to solve the hygiene problem in an interpreter. That is, it's easier to implement first-class macros (which allow hygiene) in an intepreter , than it is to implement scheme-style non-first-class hygienic macros... I only say this because I know how to implement first-class macros, but I don't really understand how Scheme's hygienic macros work...