Scheduled Updates allows reports to be cached. These can help reports that take a very long time, to open much quicker. Also the schedule can be set for various frequencies.
But it seems the process deletes the old cache before starting a new cache.
It would be good, if there was an option, to keep old cache available, while new cache is being generated. This then removes times when users are unable to use a cached copy, because they opened the report at the wrong time.