I don't get that implication from the article at all. What I do get is that the only transaction isolation level available under CockroachDB is serializable. An

I don't get that implication from the article at all. What I do get is that the only transaction isolation level available under CockroachDB is serializable. And to show why serializable is valuable, they have to demonstrate using Postgres' default of read committed (because they would be unable to demonstrate this using CockroachDB which doesn't allow any other transaction isolation levels.