The link to session is a red herring - most people seeing it won't be able to access the transcript.

It's a tag with an UID. It's useful to connect together multiple changes, including possibly several commits across multiple unrelated repositories, as well as other artifacts and actions. It records the causal link, and connects it to telemetry (people do run their own telemetry over agents, especially in team/company setting). Because chances are that, if you have issues with some change made by AI, being able to look up what other changes were made as part of the same session is going to be very helpful.

> That's not even bringing into the fact that there are people who use multiple models, multiple sessions, multiple harnesses across the same commits/changesets. How do you reconcile those alongside people who could have made human changes in the end?

This is exactly how. By tagging changes with session UID, and using it as key to resolve other changes, as well as specific model and harness versions used, if you use telemetry endpoints harnesses tend to offer.

The whole discussion is just people getting tripped over the tag being link-shaped, ie. "https://what.tld/<uid>", instead of "WHAT_ID=<uid>".