There's a couple of reasons why koha-run-backups should be the first job in /etc/cron.daily/koha-common. 1. It takes a backup before running scripts that change database contents. If there is a problem with those scripts, you'll have a very recent backup on which to fallback. 2. It's a resource intensive job. If you have a lot of Koha instances, this means you're running your most intensive job at the end of the job run, which might be a lot later in the day than you anticipate. (Of course, you can update /etc/crontab to change when /etc/cron.daily is run, but this will help reduce impact in the meantime.)