for event store databases, you'll need to have some sortable sequence ID-- you can't always even use timestamps, since on occasion you'll get multiple events happening at exactly the same time, and you still need to sequence based on received order.
Well, event stores are a very specific type of database that exists solely for the purpose of knowing exactly the order of events. It's not fair to say UUIDs are a problem because one very specific case shouldn't use it.
Definitely not! In fact, I use UUIDs everywhere else but the event store. I was just pointing out one case where having an int (well, bigint) primary key is actively useful, and UUIDs aren't.
