I think this comment re-enforced my sense the author wanted to drive to a destination and didn't want to divert down a road of "why LISP homoiconic is different

I think this comment re-enforced my sense the author wanted to drive to a destination and didn't want to divert down a road of "why LISP homoiconic is different to eval()" which I think was .. lazy. The idea has merit. Having the REPL deal with the parse structure of data in such a way that taking parsed data and presenting it as code has a lower barrier to effective outcome on the current run state than eval() is pretty big. I'd say eval() isn't self-modifying. You can't come out the other side of eval() with future execution state of yourself different. As I understand it, the homoiconic features of LISP means you can.