I am not certain what your specialist is getting at when he says, "With a manual backup you are always guaranteed to lose data." A manual backup grabs all of the same files and databases that an automated backup would.
When you do a backup, and then your site crashes a day later, you lose a day worth of data. If it crashes a month later, you lose a month's data. Because backups are not real-time, you will always lose data.
You would use RAID drives if not on a cloud server so that 1 failed drive doesn't result in an entire crash and outage.
You would have real-time backups in case of a major crash or major data corruption.
IMO Liquid Web hasn't been a good host since 2013.