I am not convinced thats all that better than inlining and then using an editor with support for code folding. You can still get a high level glance at the subs

I am not convinced thats all that better than inlining and then using an editor with support for code folding. You can still get a high level glance at the substeps but are 100% guaranteed that the blocks of code are never called anywhere else instead of that just being a module-enforced convention.