[Author here: Hey there Theodore -- first of all thank you so much for that other comment with first-hand knowledge about Apollo => UUID. This is the kind of priceless nugget that makes HN such an interesting place.]
From a systems perspective I can definitely see why one could reach the conclusion that if users are interacting with them directly, they're doing something wrong.
What we've seen is that IDs are routinely copied between different systems for debugging purposes. An example at least for Segment it is common to have IDs pasted into support tickets, and the search engine that indexes these will tokenize on the "-" in a UUID. The difference between finding the solution in minutes vs hours could be that two systems can be correlated by searching using the UUID. Leaving these out is a minor tweak that pays dividends over time.
For anything human-exposed (and in JSON or URLs) we use the 27-byte base62 encoding. In the database we store KSUIDs in their 20-byte binary (base256?) encoding.
From a systems perspective I can definitely see why one could reach the conclusion that if users are interacting with them directly, they're doing something wrong.
What we've seen is that IDs are routinely copied between different systems for debugging purposes. An example at least for Segment it is common to have IDs pasted into support tickets, and the search engine that indexes these will tokenize on the "-" in a UUID. The difference between finding the solution in minutes vs hours could be that two systems can be correlated by searching using the UUID. Leaving these out is a minor tweak that pays dividends over time.
For anything human-exposed (and in JSON or URLs) we use the 27-byte base62 encoding. In the database we store KSUIDs in their 20-byte binary (base256?) encoding.