As long as the test suite is small enough to quickly run on the devs laptops the gains from CI are fairly minimal. With old school Capistrano-rails you can deploy in 20 seconds and roll back in 5 seconds, IMHO you don't need to pay the price of multi-minute deploys until much later in a project's lifecycle.
I appreciate that they wanted to keep Kamal simple, but rebuilding a Docker image each time you deploy a tiny change feels like a waste. Capistrano just does a 'git pull / bundle / server restart' which seems much more elegant.
Of course, things like upgrading to a new ruby version become much harder with Capistrano's model, you need a separate process for a small release and a big release. But those things happen twice a year, on small projects you can do those manually until you have time to set up Kamal / Terraform / Ansible.
