I’m curious about debian/Dockerfile. What do you use it for? AFAICT,
it “just” builds a package automatically. Apart from the step which
fetches the current upstream source, you can already do that with
gbp-clone and git-buildpackage, right?
If I may, the Dockerfile helps in the same ways a Dockerfile can help with any other non-packaging project: nice repeatable builds, easy to read instructions for building that can also be run directly, and allows other platforms to trivially build/test the packaging. I'm one of those sleazy Gentoo types, so I don't have gbp-clone or git-buildpackage available natively on my host OS.