It functions as a good way to whet the appetite of the reader or student. SICP's meta-circular implementation occupies a kind of sweet spot, it imparts to stude

It functions as a good way to whet the appetite of the reader or student. SICP's meta-circular implementation occupies a kind of sweet spot, it imparts to students that only just grokked recursion to understand how the programming language itself is just a program they can understand and tinker with. The state machine implementation of the Scheme interpreter sort of breaks the meta-circularity to dismantle the tautologies.