In part 1, they say, "I wanted it to look like a regular for-loop from C as much as possible." The AST method seems to require you to write "with _for" instead

In part 1, they say, "I wanted it to look like a regular for-loop from C as much as possible." The AST method seems to require you to write "with _for" instead of "for". The method in part 3 allows you to write "for", which is closer. So presumably it's better because it gets closer to the objective, although at quite a cost of course.