The only thing I can think of is if the user can export data from one system and import it to another, and for some reason there was a requirement to keep the U

The only thing I can think of is if the user can export data from one system and import it to another, and for some reason there was a requirement to keep the UUIDs the same. ...or maybe if you're storing data from a remote API that uses UUID's as primary keys, and you want to make sure you catch it if they change things. Though in that case I would likely have my own primary key and store the remote primary key in a separate column