Regardless, the main point is that numbering directories as a mnemonic is more of an encumbrance than a help. The justification on the website, that it prevents new directories from disrupting the user's mental map, is unconvincing. There are many methods for that that don't require a team to align on a numbering system and fixed directory order - shortcuts, bookmarks, snippet managers, broot, and z, to name a few. Not all methods are available in all contexts, but at least some are.
Prepending numbers, on the other hand, forces users to, at best, waste time learning a system they might not need to use again or, at worst, bikeshed about what number to give a new directory or how to renumber if a change is needed. Users can't even skim directory names because the order is fixed and they've been robbed of the ability to sort alphabetically. The larger the team, the worse all this becomes.