alt Hacker NewsThere's nothing stopping you from doing so. You don't have to use strict UUIDs. Their form rarely serves a real purpose anyway.
But for exposed values (document ids, customer ids, that kind of thing), it can be awkward if a patient's id is suddenly "CRANKY-...-FART".
If I discovered that were my patient ID, I would laugh myself into unconsciousness and buy the staff a pizza.