Потому что без этого никуда.

"We built survivability into the DNA of CockroachDB. And while we had a lot of fun doing so, and are confident that we have built a solution on a firm foundation, we felt a nagging concern: Does CockroachDB really survive? When data is written to the database, will a failure really not end up in data loss? So to assuage those concerns, we adopted a Russian maxim: “Dovorey, no provorey – Trust, but Verify.”"

https://www.cockroachlabs.com/blog/trust-but-verify-cockroachdb-checks-replication/