The ability to perform a quick rollback or rewind of the database
This is along the lines of a flashback, to a previous point in time say from a very impacting change to data.. A large delete or data modification event. This avoids the need to take a complete outage for hours and hours restoring TBs of data and re-applying change logs. Would be great if this could be done to the granularity of a single or multiple collections too. This could use the oplogs present locally or in the oplog store.