I'm on 10.14.1. Anyone with a 2018 Mac mini can confirm it doesn't break basic things like booting, external usb3 drives, Photos, etc.?
In 99.9% of cases it won't break anything. The problem is no one can guarantee you won't be one of the unlucky one's where some voodoo happens and it ****s everything up.
So ... the rule is, before any update, use carbon copy cloner to image everything on your boot drive exactly as it is right before the update. Then go ahead and update! At that point you have no worries if the update somehow (unlikely) causes an issue.