Docker can be considered a deployment tool. You package your application in an image and run said image. Development and test of that application does not have to be in a docker image.
Nor does deployment. Podman, Rancher, etc all solve those challenges without relying on Docker and with Docker changing their licensing I don't think it will be the de-facto tool in a couple years. There will be others that will replace it.
Docker has become synonymous with OCI images, and my comment was exactly in that context (or at least state of mind) - I should have stated that as well.
