Paraphrasing some of my other comments - "no Dockerfile" isn't the core benefit, it's the ability to control what base images are used and rebase the base images of running containers without needing to rebuild. It's very easy to create a Dockerfile that builds an image with vulnerabilities and it's hard to discover which containers are using the compromised image. Buildpacks provides a framework to ensure your fleet of containers use compliant images and a easy way to patch vulnerabilities without needing to involve the development team