Don't uuids have the big advantage of being easy to shard,over auto incrementing ids? That's usually a big deal. The other big deal is that uuids can be create

Don't uuids have the big advantage of being easy to shard,over auto incrementing ids? That's usually a big deal. The other big deal is that uuids can be created on the client and supplied by the client. That can make a lot of code drastically simpler (idempotency comes to mind)