UUIDs are 128-bit numbers and the hyphenated-string representation is only one of many ways to represent that number, sort of like how an IPv4 address is a 32-b

UUIDs are 128-bit numbers and the hyphenated-string representation is only one of many ways to represent that number, sort of like how an IPv4 address is a 32-bit number of which the “dotted-quad” is only one representation. If you are thinking of UUID as a string format then your most fundamental concept of UUID is flawed. Even if you do just want a random identifier (not really the original point of UUID but has become their most popular form) I still think it's cool how random UUIDs have a little flag bit to tell you that it's intended to be random. Useful when one runs across a lone identifier with zero context.