Comment by cryptonector

> For example, it's trivial from a web browser with a couple of clicks to go and find out all the downstream changes to a package.

How is this not also true for Git? Just put all the Debian commits "on top" and use an appropriate naming convention for your branches and tags.

> If everything gets merged in the same git tree it's way harder.

Yes, so don't merge, just rebase.

> Harder but doable with a rebase+force push workflow, which makes collaboration way harder.

No force pushes, just use new branch/tag names for new releases.

> Just impossible with a merge workflow.

Not impossible but dumb. Don't use merge workflows!

> As an upstream maintainer of several project, being able to tell at a glance and with a few clicks how one of my projects is patched in a distribution is immensely useful when bug reports are opened.

Git with a suitable web front-end gives you exactly that.

> In a past job it also literally saved a ton of money because we could show legal how various upstreams were customized by providing the content of a few .debian.tar.gz tarballs with a few small, detached patches that could be analyzed, instead of massive upstream trees that would take orders of magnitude more time to go through.

`git format-patch` and related can do the moral equivalent.