Procedures are very useful to enforce business logic in the database, rather than in the application. It’s like putting a higher level application-specific API on top of your database schema.

For Cockroach, it could help substantially with latency for multi-statement transactions, since the procedure could be executed on a database node closest to the leaseholder for the data. Executing a multi-statement transaction on the client means incurring per-statement latency between the client and gateway node, and between the gateway node and the leaseholder.