I see you understood the point made by the example.
For nuclear weapons specifically, the activation code was supposed to be a command and control measure to prevent unauthorized use. Having it both be an easily remembered code and one widely known made that whole system meaningless theatre.
4567
While 0 has no value and is often placed after 9 on keyboards, you asked about digits in a base and not numbers. This becomes clear if you describe the various bases.
If you sort zero at the end, you’d need to spell out the digits or label them all as 1-0, which isn’t very descriptive.
Mind you, “zero-first ordering of digits” is not a fundamental rule, since the glyphs only have a need to be sorted when they stand for a numerical value . And if you used a phrase like “first X digits” without noting a range the omission would be a composition error.