Which is precisely my point. As one other commenter said: "who have you been talking to?". Executing code at compile-time is a great idea in general, maybe those experts were talking about a very particular problem? It's not clear.
Well, to criticize something people start (and, often, end) on concrete examples they've seen it in practice. And for "compile time code generation" C++ templates are an example they'd be familiar with (perhaps the canonical one, as more people know C++ than Lisp).
