Good point. Imagine the developers of Postgres or Mongo would do CD to your database. IMO, the idea of CD only works for companies that control the production

Good point. Imagine the developers of Postgres or Mongo would do CD to your database. IMO, the idea of CD only works for companies that control the production environment and basically offer a service, not a product. If that's you, you may get a great deal out of CD. But if you have a product and if that product manages your customer's data, is integrated with your customer's scripts, and runs on an environment that you don't completely control, you better think twice before permanently updating the system. You can still do it, but it will be expensive to get it right.