GUIDs are not human friendly.
Anyone who dealt with Advanced Queueing and had to look for messages in queue tables knows that.
I have seen many database applications naively relying on uniqueness of GUIDs (or UUIDs).
Pity those poor souls who maintain and troubleshoot those apps.
Why? Just try to read a GUID over the phone.
Or try to find differences between the following two strings:
oracle aide 