Fantastic real life example. Italian PNs carry also the gender, which something you can change surgically, and you'll eventually run into the issue when operating at scale.

I don't agree with the absolute statement, though. Permanent identifiers should not generally carry data. There are situations where you want to have a way to reconciliate, you have space or speed constraints, so you may accept the trade off, md5 your data and store it in a primary index as a UUID. Your index will fragment and thus you will vacuum, but life will still be good overall.