Allow tags to be added (and created) in journeys that are based on a merge strategy e.g. “Add tag = {{latest_activity.some_field}}”
So when a journey is triggered by a salesforce activity a tag can be added that pulls in the value of one of the activity attributes.
Reason this is useful is so we can use those tags to target within liquid code, that doesn't work on activity data. Another solution would be to make liquid code work using activity attributes beyond 30 days if that's simpler.