Designer 4.8 Early Access: git for packages

Playing around with Deisgner 4.8 from the Early Access refresh and having watched the demo video, I'm still wondering what development workflow is envisioned by using git for packages. The demo shows how to build and publish packages to git but not how to pull packages out of it again.

Looks like Designer does not store packages in git in as a Package Update Repo (i.e. with site.xml and features/plugins/deprecations subfolders) but only as plugin jars in a flat folder (like in the "plugins" subfolder of an Online Repo) so a git working tree cannot be used as a local Online Repository in Designer.

Git is about sharing with others, so how am I supposed to use a package someone shared through a git repo with me in my Designer projects? Manually import the file into each project's Package Catalog?

I also do not get the idea of both building and publishing to a git repo? Up until now I thought of a git package repo as an alternative to Online Repositories and do not (yet) see a point in putting unreleased packages (that might have their content and build number changed anytime and therefore may cause trouble if distributed and deployed/imported to/from any project other than the one where the package is developed).

Personally I never distribute unreleased packages because their content may change and older build are usually not available anymore. How do others work with unreleased packages? Do you see a use case to put them under version control and share them? How does your dev workflow looks like in that case?