People keep saying “just use Git commits” without understanding the advantages of the Quilt approach. There are tools to keep patches as Git commits that solve this, but “just Git commits” do not.
I rather suspect that "commit messages on changes to patches" is what Debian ended up with and back-justifies it.
Of course, I am not a Debian maintainer, so it's entirely possible I'm just missing the experience of it that would make me want "commit messages on changes to patches".
I’m not arguing against replacing Quilt, but it should be more than just Git. I haven’t done Debian packaging in a long time but apparently there are some Git-based tools now?