Yeah its hard to get folks to come into the modern age of computering. FOr some reason there's tremendous resistance to abandoning the old crusty buggy solutions (indexes and handles that collide and need remapping) and using stuff that just works (identifying everything immutable with a uuid). Folks say 'its too many bits' and 'it takes too long'. Then they proceed to write megabytes worth of patchy code to try and save 64 bits worth of identifier.

As for database efficiency, that's a problem. But its a problem with the database - certainly no comfort for the user. But databases could do better, and I think they will one day come to handle uuids with less grief to the developer.

They already do. Postgres and SQL Server have UUID types.

Yeah, exactly. Building weakness into one's protocol because of an unhealthy attachment to saving a few bits and an even more unhealthy attachment to MySQL just seems foolish.

If you work with large amounts of data it hugely matters. 16 bytes times 1 billion records ends up being way more than 16GB of data, indexes, foreign keys, hot backup, etc. to manage and query.

Even that is a small amount of memory. I have that much RAM on my computer. See, its an obsolete conversation, yet folks raised in an ecology of scarcity can't get past it.

It depends on what you are optimizing for. If you need to store your entire database in physical memory, then the difference between 16GB and 128MB is significant.