I'm sure I take bigger penalty hits for less, sorry but UUID's "click" in my head and they prevent a whole slew of foot-guns. It would be one thing if auto-inc was the same as UUID but there are really annoying things with auto-inc (not knowing the id until after insert being top of mind) and also you can generate UUID's client-side/offline if needed. Yes, I know some people argue for auto-inc as primary and still use UUID for client-facing but I don't understand what that really gets you and it seems way more complicated.