Earlier quoted context omitted.
The former. We found it really useful to see, in a way that you could read and ignore, who was committing what to where. It helped you keep up with what was going on, who was working where in the codebase, when things that might impact you changed, etc, all without any explicit effort save for writing decent commit messages. Particularly when you're all in different timezones, that kind of casual background knowledge…
In my expirience people tend to ignore autogenerated messages in Slack. The problem is non-technical people who are too lazy to read git commit messages, or PRs. I had some Scrum PM who was bothering me with updates, so I was just copy-pasting git commit messages into Jira tickets (commit messages even mentioned the Jira ticket numbers - so it was just one hyperlink click away) ;) Only top-level executives deserve ca…
The thing we used had a scrolling tickertape-style window. Commit messages would scroll across once, and then they were in the history. So if you were online, you could glance at the committer, and commit message, and that was it. No need to switch to the channel, click anywhere, or do anything, it was just ... there, and then gone.
The history window was similar. It was threaded (replies indented under the message they responded to), but everything was in one list by default. So you could just skim down, and catch up on what was done pretty simply: no clicking into groups, no looking at message counts, etc.
Slack is really not the best UX, in my experience.