The ability to mix different types of ID in one column or one business data store. When you start with random UUIDs, and then decide you actually wanted per-ho

The ability to mix different types of ID in one column or one business data store. When you start with random UUIDs, and then decide you actually wanted per-host-namespaced ones halfway through, if you have allocated zero bits for the version ID you're up the creek. You're trading off present-day efficiency for future-day flexibility. Whether that's wise for a particular case depends on that case.