If you have data-driven tests that compute UUIDs along the way to their results, plopping in an UUID generator that is a predictable hash algo is a good thing.

This is similar to C rand(), which you wouldn't want to use in production but is useful when generating the same test data for the same seed every time.

It is a hash, but in the format of a UUID. This is useful if you are storing it in the database, since there is usually a dedicated data type for UUIDs. Also, you can mix UUID v4 and v5 IDs freely.

Think an MD5 hash is the exact same length as a UUID, so you can just put hyphens in. Same thing for truncated SHA-N :-P