> history is a stream of content-addressed commits
Not quite true for mercurial. You also get stable identifiers for commits that remain the same even after being manipulated such as after rebases or amends. It also enables tracking the evolution of a changeset which then enables `hg evolve`.
Being content addressable isn’t a desirable feature in a user-friendly version control system. Who cares about it? Giving stable identifiers to commits is a much more needed feature.
Have you used Jujutsu before? It's git-backed and it sounds like it incorporates a lot of these niceties from Mercurial. I find it an awful lot more intuitive than Git to use and the stable identifiers are absolutely lovely to have.
You mean "git tag"?
If you tag every commit, sure. You don't know which commit has a bug that needs to be fixed in advance. And at the point you're tagging every commit, you're fighting git.
EDIT: reconsidering: you would have to move a tag when you make changes. A tag is just giving a name to a commit, not a stable identifier that follows a change. A branch is a more appropriate analogy.
A git-native workflow for this would be to have a sequence of branches you continue to update, where 'main' is those branches merged at all times.