[feydaykyn]

A dev at $WORK thought it wasn't a big deal too because they "tested" on their unrestricted dev setup with 3 rows in the table.

Of course production crashed when their latest sql query did a multijoin on the real table with a few millions of rows. The size of the uuid needed to join filled the available RAM, everything slowed to a crawl and the system collapsed.

The uuid as primary key can be seen as a risk multiplicator : it will amplify any performance issue you may have, converting a temporary slowness into a full system stop.