[xuejie]

This is really depending on your view, but the moment you step outside of lists and use arrays, you are keeping modern CPU architecture in mind. And all of a sudden all those wonder car/cdr/cons concepts as well as things built upon it no longer holds, which, again depending on the view, actually harms the abstractions in Lisp, and we are actually back at the same page with all the other programming languages.

Also, when you are promoting something, it might not a good idea to compare against Python when it comes to speed, but when talking maintainability, only C is talking as a target here.