Regarding the noise you mention, I wonder if memento's use of the git 'notes' feature is an acceptable way to contain or quarantine that noise. It might still not add much value, but at least it would live in a separate place that is easily filtered out when the user judges it irrelevant. Per the README of the linked repo,

> It runs a commit and then stores a cleaned markdown conversation as a git note on the new commit.

So it doesn't seem that normal commit history is affected - git stores notes specially, outside of the commit (https://git-scm.com/docs/git-notes).

In fact github doesn't even display them, according to some (two-year-old) blog posts I'm seeing. Not sure about other interfaces to git (magit, other forges), but git log is definitely able to ignore them (https://git-scm.com/docs/git-log#Documentation/git-log.txt--...).

This doesn't mean the saved artifacts would necessarily be valuable - just that, unlike a more naive solution (saving in commit messages or in some directory of tracked files) they may not get in the way of ordinary workflows aside from maybe bloating the repo to some degree.